diff --git a/CHANGELOG.md b/CHANGELOG.md
index 370864cb..6b06cb75 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,34 +1,39 @@
-## Unreleased
+## Master
 
-* Fix printing for inline nullary functor types [#477](https://github.com/rescript-lang/syntax/pull/477)
-* Fix stripping of quotes for empty poly variants [#474](https://github.com/rescript-lang/syntax/pull/474)
-* Implement syntax for arity zero vs arity one in uncurried application in [#139](https://github.com/rescript-lang/syntax/pull/139)
-* Fix parsing of first class module exprs as part of binary/ternary expr in [#256](https://github.com/rescript-lang/syntax/pull/256)
-* Fix formatter hanging on deeply nested function calls [#261](https://github.com/rescript-lang/syntax/issues/261)
-* Remove parsing of "import" and "export" which was never officially supported.
+#### :rocket: New Feature
 
-## ReScript 9.0.0
+- Add surface syntax for `async`/`await` https://github.com/rescript-lang/syntax/pull/600
+
+## ReScript 10.0
 
-* Fix parsing of poly-var typexpr consisting of one tag-spec-first in [#254](https://github.com/rescript-lang/syntax/pull/254)
-* Implement new syntax for guards on pattern match cases in [#248](https://github.com/rescript-lang/syntax/pull/248)
-* Implement intelligent breaking for poly-var type expressions in [#246](https://github.com/rescript-lang/syntax/pull/246)
-* Improve indentation of fast pipe chain in let binding in [#244](https://github.com/rescript-lang/syntax/pull/244)
-* Improve printing of non-callback arguments in call expressions with callback in [#241](https://github.com/rescript-lang/syntax/pull/241/files)
-* Fix printing of constrained expressions in rhs of js objects [#240](https://github.com/rescript-lang/syntax/pull/240)
-* Improve printing of trailing comments under lhs of "pipe" expression in [#329](https://github.com/rescript-lang/syntax/pull/239/files)
-* Improve printing of jsx children and props with leading line comment in [#236](https://github.com/rescript-lang/syntax/pull/236)
-* Improve conversion of quoted strings from Reason in [#238](https://github.com/rescript-lang/syntax/pull/238)
-* Print attributes/extension without bs prefix where possible in [#230](https://github.com/rescript-lang/syntax/pull/230)
-* Cleanup gentype attribute printing [fe05e1051aa94b16f6993ddc5ba9651f89e86907](https://github.com/rescript-lang/syntax/commit/fe05e1051aa94b16f6993ddc5ba9651f89e86907)
-* Implement light weight syntax for poly-variants [f84c5760b3f743f65e934195c87fc06bf88bff75](https://github.com/rescript-lang/syntax/commit/f84c5760b3f743f65e934195c87fc06bf88bff75)
-* Fix bug in fast pipe conversion from Reason. [3d5f2daba5418b821c577ba03e2de1afb0dd66de](https://github.com/rescript-lang/syntax/commit/3d5f2daba5418b821c577ba03e2de1afb0dd66de)
-* Improve parsed AST when tilde is missing in arrow expr parameters. [e52a0c89ac39b578a2062ef15fae2be625962e1f](https://github.com/rescript-lang/syntax/commit/e52a0c89ac39b578a2062ef15fae2be625962e1f)
-* Improve parser diagnostics for missing tilde in labeled parameters. [a0d7689d5d2bfc31dc251e966ac33a3001200171](https://github.com/rescript-lang/syntax/commit/a0d7689d5d2bfc31dc251e966ac33a3001200171)
-* Improve printing of uncurried application with a huggable expression in [c8767215186982e171fe9f9101d518150a65f0d7](https://github.com/rescript-lang/syntax/commit/c8767215186982e171fe9f9101d518150a65f0d7)
-* Improve printing of uncurried arrow typexpr outcome printer in [4d953b668cf47358deccb8b730566f24de25b9ee](https://github.com/rescript-lang/syntax/commit/4d953b668cf47358deccb8b730566f24de25b9ee)
-* Remove support for nativeint syntax in [72d9b7034fc28f317672c94994b322bee520acca](https://github.com/rescript-lang/syntax/commit/72d9b7034fc28f317672c94994b322bee520acca)
-* Improve printing of poly variant typexprs with attributes in [bf6561b](https://github.com/rescript-lang/syntax/commit/bf6561bb5d84557b8b6cbbcd40078c39526af4af) 
+- Fix printing for inline nullary functor types [#477](https://github.com/rescript-lang/syntax/pull/477)
+- Fix stripping of quotes for empty poly variants [#474](https://github.com/rescript-lang/syntax/pull/474)
+- Implement syntax for arity zero vs arity one in uncurried application in [#139](https://github.com/rescript-lang/syntax/pull/139)
+- Fix parsing of first class module exprs as part of binary/ternary expr in [#256](https://github.com/rescript-lang/syntax/pull/256)
+- Fix formatter hanging on deeply nested function calls [#261](https://github.com/rescript-lang/syntax/issues/261)
+- Remove parsing of "import" and "export" which was never officially supported.
+
+## ReScript 9.0.0
 
+- Fix parsing of poly-var typexpr consisting of one tag-spec-first in [#254](https://github.com/rescript-lang/syntax/pull/254)
+- Implement new syntax for guards on pattern match cases in [#248](https://github.com/rescript-lang/syntax/pull/248)
+- Implement intelligent breaking for poly-var type expressions in [#246](https://github.com/rescript-lang/syntax/pull/246)
+- Improve indentation of fast pipe chain in let binding in [#244](https://github.com/rescript-lang/syntax/pull/244)
+- Improve printing of non-callback arguments in call expressions with callback in [#241](https://github.com/rescript-lang/syntax/pull/241/files)
+- Fix printing of constrained expressions in rhs of js objects [#240](https://github.com/rescript-lang/syntax/pull/240)
+- Improve printing of trailing comments under lhs of "pipe" expression in [#329](https://github.com/rescript-lang/syntax/pull/239/files)
+- Improve printing of jsx children and props with leading line comment in [#236](https://github.com/rescript-lang/syntax/pull/236)
+- Improve conversion of quoted strings from Reason in [#238](https://github.com/rescript-lang/syntax/pull/238)
+- Print attributes/extension without bs prefix where possible in [#230](https://github.com/rescript-lang/syntax/pull/230)
+- Cleanup gentype attribute printing [fe05e1051aa94b16f6993ddc5ba9651f89e86907](https://github.com/rescript-lang/syntax/commit/fe05e1051aa94b16f6993ddc5ba9651f89e86907)
+- Implement light weight syntax for poly-variants [f84c5760b3f743f65e934195c87fc06bf88bff75](https://github.com/rescript-lang/syntax/commit/f84c5760b3f743f65e934195c87fc06bf88bff75)
+- Fix bug in fast pipe conversion from Reason. [3d5f2daba5418b821c577ba03e2de1afb0dd66de](https://github.com/rescript-lang/syntax/commit/3d5f2daba5418b821c577ba03e2de1afb0dd66de)
+- Improve parsed AST when tilde is missing in arrow expr parameters. [e52a0c89ac39b578a2062ef15fae2be625962e1f](https://github.com/rescript-lang/syntax/commit/e52a0c89ac39b578a2062ef15fae2be625962e1f)
+- Improve parser diagnostics for missing tilde in labeled parameters. [a0d7689d5d2bfc31dc251e966ac33a3001200171](https://github.com/rescript-lang/syntax/commit/a0d7689d5d2bfc31dc251e966ac33a3001200171)
+- Improve printing of uncurried application with a huggable expression in [c8767215186982e171fe9f9101d518150a65f0d7](https://github.com/rescript-lang/syntax/commit/c8767215186982e171fe9f9101d518150a65f0d7)
+- Improve printing of uncurried arrow typexpr outcome printer in [4d953b668cf47358deccb8b730566f24de25b9ee](https://github.com/rescript-lang/syntax/commit/4d953b668cf47358deccb8b730566f24de25b9ee)
+- Remove support for nativeint syntax in [72d9b7034fc28f317672c94994b322bee520acca](https://github.com/rescript-lang/syntax/commit/72d9b7034fc28f317672c94994b322bee520acca)
+- Improve printing of poly variant typexprs with attributes in [bf6561b](https://github.com/rescript-lang/syntax/commit/bf6561bb5d84557b8b6cbbcd40078c39526af4af)
 
 ## ReScript 8.4.2 (December 11, 2020)
 
diff --git a/src/res_core.ml b/src/res_core.ml
index 506ceea3..0d53ed16 100644
--- a/src/res_core.ml
+++ b/src/res_core.ml
@@ -161,6 +161,8 @@ let uncurryAttr = (Location.mknoloc "bs", Parsetree.PStr [])
 let ternaryAttr = (Location.mknoloc "ns.ternary", Parsetree.PStr [])
 let ifLetAttr = (Location.mknoloc "ns.iflet", Parsetree.PStr [])
 let optionalAttr = (Location.mknoloc "ns.optional", Parsetree.PStr [])
+let makeAwaitAttr loc = (Location.mkloc "res.await" loc, Parsetree.PStr [])
+let makeAsyncAttr loc = (Location.mkloc "res.async" loc, Parsetree.PStr [])
 
 let makeExpressionOptional ~optional (e : Parsetree.expression) =
   if optional then {e with pexp_attributes = optionalAttr :: e.pexp_attributes}
@@ -237,6 +239,9 @@ let rec goToClosing closingToken state =
 (* Madness *)
 let isEs6ArrowExpression ~inTernary p =
   Parser.lookahead p (fun state ->
+      (match state.Parser.token with
+      | Lident "async" -> Parser.next state
+      | _ -> ());
       match state.Parser.token with
       | Lident _ | Underscore -> (
         Parser.next state;
@@ -2031,6 +2036,16 @@ and parseOperandExpr ~context p =
       let expr = parseUnaryExpr p in
       let loc = mkLoc startPos p.prevEndPos in
       Ast_helper.Exp.assert_ ~loc expr
+    | Lident "async"
+    (* we need to be careful when we're in a ternary true branch:
+       `condition ? ternary-true-branch : false-branch`
+       Arrow expressions could be of the form: `async (): int => stuff()`
+       But if we're in a ternary, the `:` of the ternary takes precedence
+    *)
+      when isEs6ArrowExpression ~inTernary:(context = TernaryTrueBranchExpr) p
+      ->
+      parseAsyncArrowExpression p
+    | Await -> parseAwaitExpression p
     | Lazy ->
       Parser.next p;
       let expr = parseUnaryExpr p in
@@ -2744,6 +2759,21 @@ and parseBracedOrRecordExpr p =
     let expr = parseRecordExpr ~startPos [] p in
     Parser.expect Rbrace p;
     expr
+  (*
+    The branch below takes care of the "braced" expression {async}.
+    The big reason that we need all these branches is that {x} isn't a record with a punned field x, but a braced expression… There's lots of "ambiguity" between a record with a single punned field and a braced expression…
+    What is {x}?
+      1) record {x: x}
+      2) expression x which happens to wrapped in braces
+    Due to historical reasons, we always follow 2
+  *)
+  | Lident "async" when isEs6ArrowExpression ~inTernary:false p ->
+    let expr = parseAsyncArrowExpression p in
+    let expr = parseExprBlock ~first:expr p in
+    Parser.expect Rbrace p;
+    let loc = mkLoc startPos p.prevEndPos in
+    let braces = makeBracesAttr loc in
+    {expr with pexp_attributes = braces :: expr.pexp_attributes}
   | Uident _ | Lident _ -> (
     let startToken = p.token in
     let valueOrConstructor = parseValueOrConstructor p in
@@ -3099,6 +3129,28 @@ and parseExprBlock ?first p =
   Parser.eatBreadcrumb p;
   overParseConstrainedOrCoercedOrArrowExpression p blockExpr
 
+and parseAsyncArrowExpression p =
+  let startPos = p.Parser.startPos in
+  Parser.expect (Lident "async") p;
+  let asyncAttr = makeAsyncAttr (mkLoc startPos p.prevEndPos) in
+  let expr = parseEs6ArrowExpression p in
+  {
+    expr with
+    pexp_attributes = asyncAttr :: expr.pexp_attributes;
+    pexp_loc = {expr.pexp_loc with loc_start = startPos};
+  }
+
+and parseAwaitExpression p =
+  let awaitLoc = mkLoc p.Parser.startPos p.endPos in
+  let awaitAttr = makeAwaitAttr awaitLoc in
+  Parser.expect Await p;
+  let expr = parseUnaryExpr p in
+  {
+    expr with
+    pexp_attributes = awaitAttr :: expr.pexp_attributes;
+    pexp_loc = {expr.pexp_loc with loc_start = awaitLoc.loc_start};
+  }
+
 and parseTryExpression p =
   let startPos = p.Parser.startPos in
   Parser.expect Try p;
diff --git a/src/res_grammar.ml b/src/res_grammar.ml
index 44f0e497..cba9b4bd 100644
--- a/src/res_grammar.ml
+++ b/src/res_grammar.ml
@@ -147,11 +147,11 @@ let isAtomicTypExprStart = function
   | _ -> false
 
 let isExprStart = function
-  | Token.True | False | Int _ | String _ | Float _ | Codepoint _ | Backtick
-  | Underscore (* _ => doThings() *)
-  | Uident _ | Lident _ | Hash | Lparen | List | Module | Lbracket | Lbrace
-  | LessThan | Minus | MinusDot | Plus | PlusDot | Bang | Percent | At | If
-  | Switch | While | For | Assert | Lazy | Try ->
+  | Token.Assert | At | Await | Backtick | Bang | Codepoint _ | False | Float _
+  | For | Hash | If | Int _ | Lazy | Lbrace | Lbracket | LessThan | Lident _
+  | List | Lparen | Minus | MinusDot | Module | Percent | Plus | PlusDot
+  | String _ | Switch | True | Try | Uident _ | Underscore (* _ => doThings() *)
+  | While ->
     true
   | _ -> false
 
@@ -255,11 +255,11 @@ let isAttributeStart = function
 let isJsxChildStart = isAtomicExprStart
 
 let isBlockExprStart = function
-  | Token.At | Hash | Percent | Minus | MinusDot | Plus | PlusDot | Bang | True
-  | False | Float _ | Int _ | String _ | Codepoint _ | Lident _ | Uident _
-  | Lparen | List | Lbracket | Lbrace | Forwardslash | Assert | Lazy | If | For
-  | While | Switch | Open | Module | Exception | Let | LessThan | Backtick | Try
-  | Underscore ->
+  | Token.Assert | At | Await | Backtick | Bang | Codepoint _ | Exception
+  | False | Float _ | For | Forwardslash | Hash | If | Int _ | Lazy | Lbrace
+  | Lbracket | LessThan | Let | Lident _ | List | Lparen | Minus | MinusDot
+  | Module | Open | Percent | Plus | PlusDot | String _ | Switch | True | Try
+  | Uident _ | Underscore | While ->
     true
   | _ -> false
 
diff --git a/src/res_parens.ml b/src/res_parens.ml
index 33fb0f3d..c18b7565 100644
--- a/src/res_parens.ml
+++ b/src/res_parens.ml
@@ -45,6 +45,8 @@ let callExpr expr =
        | Pexp_try _ | Pexp_while _ | Pexp_for _ | Pexp_ifthenelse _ );
     } ->
       Parenthesized
+    | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+      Parenthesized
     | _ -> Nothing)
 
 let structureExpr expr =
@@ -96,6 +98,8 @@ let unaryExprOperand expr =
        | Pexp_try _ | Pexp_while _ | Pexp_for _ | Pexp_ifthenelse _ );
     } ->
       Parenthesized
+    | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+      Parenthesized
     | _ -> Nothing)
 
 let binaryExprOperand ~isLhs expr =
@@ -120,6 +124,8 @@ let binaryExprOperand ~isLhs expr =
     | expr when ParsetreeViewer.isBinaryExpression expr -> Parenthesized
     | expr when ParsetreeViewer.isTernaryExpr expr -> Parenthesized
     | {pexp_desc = Pexp_lazy _ | Pexp_assert _} when isLhs -> Parenthesized
+    | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+      Parenthesized
     | {Parsetree.pexp_attributes = attrs} ->
       if ParsetreeViewer.hasPrintableAttributes attrs then Parenthesized
       else Nothing)
@@ -169,7 +175,7 @@ let flattenOperandRhs parentOperator rhs =
   | _ when ParsetreeViewer.isTernaryExpr rhs -> true
   | _ -> false
 
-let lazyOrAssertExprRhs expr =
+let lazyOrAssertOrAwaitExprRhs expr =
   let optBraces, _ = ParsetreeViewer.processBracesAttr expr in
   match optBraces with
   | Some ({Location.loc = bracesLoc}, _) -> Braced bracesLoc
@@ -196,6 +202,8 @@ let lazyOrAssertExprRhs expr =
        | Pexp_try _ | Pexp_while _ | Pexp_for _ | Pexp_ifthenelse _ );
     } ->
       Parenthesized
+    | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+      Parenthesized
     | _ -> Nothing)
 
 let isNegativeConstant constant =
@@ -240,6 +248,8 @@ let fieldExpr expr =
        | Pexp_ifthenelse _ );
     } ->
       Parenthesized
+    | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+      Parenthesized
     | _ -> Nothing)
 
 let setFieldExprRhs expr =
@@ -302,6 +312,8 @@ let jsxPropExpr expr =
       }
         when startsWithMinus x ->
         Parenthesized
+      | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+        Parenthesized
       | {
        Parsetree.pexp_desc =
          ( Pexp_ident _ | Pexp_constant _ | Pexp_field _ | Pexp_construct _
@@ -338,6 +350,8 @@ let jsxChildExpr expr =
       }
         when startsWithMinus x ->
         Parenthesized
+      | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+        Parenthesized
       | {
        Parsetree.pexp_desc =
          ( Pexp_ident _ | Pexp_constant _ | Pexp_field _ | Pexp_construct _
diff --git a/src/res_parens.mli b/src/res_parens.mli
index 04cca4b8..cedf98e1 100644
--- a/src/res_parens.mli
+++ b/src/res_parens.mli
@@ -10,7 +10,7 @@ val subBinaryExprOperand : string -> string -> bool
 val rhsBinaryExprOperand : string -> Parsetree.expression -> bool
 val flattenOperandRhs : string -> Parsetree.expression -> bool
 
-val lazyOrAssertExprRhs : Parsetree.expression -> kind
+val lazyOrAssertOrAwaitExprRhs : Parsetree.expression -> kind
 
 val fieldExpr : Parsetree.expression -> kind
 
diff --git a/src/res_parsetree_viewer.ml b/src/res_parsetree_viewer.ml
index 8049d6a9..c22dfb23 100644
--- a/src/res_parsetree_viewer.ml
+++ b/src/res_parsetree_viewer.ml
@@ -11,7 +11,7 @@ let arrowType ct =
       process attrsBefore (arg :: acc) typ2
     | {
      ptyp_desc = Ptyp_arrow ((Nolabel as lbl), typ1, typ2);
-     ptyp_attributes = [({txt = "bs"}, _)] as attrs;
+     ptyp_attributes = [({txt = "bs" | "res.async"}, _)] as attrs;
     } ->
       let arg = (attrs, lbl, typ1) in
       process attrsBefore (arg :: acc) typ2
@@ -55,6 +55,30 @@ let processUncurriedAttribute attrs =
   in
   process false [] attrs
 
+type functionAttributesInfo = {
+  async: bool;
+  uncurried: bool;
+  attributes: Parsetree.attributes;
+}
+
+let processFunctionAttributes attrs =
+  let rec process async uncurried acc attrs =
+    match attrs with
+    | [] -> {async; uncurried; attributes = List.rev acc}
+    | ({Location.txt = "bs"}, _) :: rest -> process async true acc rest
+    | ({Location.txt = "res.async"}, _) :: rest ->
+      process true uncurried acc rest
+    | attr :: rest -> process async uncurried (attr :: acc) rest
+  in
+  process false false [] attrs
+
+let hasAwaitAttribute attrs =
+  List.exists
+    (function
+      | {Location.txt = "res.await"}, _ -> true
+      | _ -> false)
+    attrs
+
 let collectListExpressions expr =
   let rec collect acc expr =
     match expr.pexp_desc with
@@ -168,8 +192,9 @@ let filterParsingAttrs attrs =
       match attr with
       | ( {
             Location.txt =
-              ( "ns.ternary" | "ns.braces" | "res.template" | "bs" | "ns.iflet"
-              | "ns.namedArgLoc" | "ns.optional" );
+              ( "bs" | "ns.braces" | "ns.iflet" | "ns.namedArgLoc"
+              | "ns.optional" | "ns.ternary" | "res.async" | "res.await"
+              | "res.template" );
           },
           _ ) ->
         false
@@ -316,7 +341,8 @@ let hasAttributes attrs =
       match attr with
       | ( {
             Location.txt =
-              "bs" | "res.template" | "ns.ternary" | "ns.braces" | "ns.iflet";
+              ( "bs" | "ns.braces" | "ns.iflet" | "ns.ternary" | "res.async"
+              | "res.await" | "res.template" );
           },
           _ ) ->
         false
@@ -497,8 +523,8 @@ let isPrintableAttribute attr =
   match attr with
   | ( {
         Location.txt =
-          ( "bs" | "res.template" | "ns.ternary" | "ns.braces" | "ns.iflet"
-          | "JSX" );
+          ( "bs" | "ns.iflet" | "ns.braces" | "JSX" | "res.async" | "res.await"
+          | "res.template" | "ns.ternary" );
       },
       _ ) ->
     false
diff --git a/src/res_parsetree_viewer.mli b/src/res_parsetree_viewer.mli
index e492010b..f1f5fa32 100644
--- a/src/res_parsetree_viewer.mli
+++ b/src/res_parsetree_viewer.mli
@@ -17,6 +17,17 @@ val functorType :
 val processUncurriedAttribute :
   Parsetree.attributes -> bool * Parsetree.attributes
 
+type functionAttributesInfo = {
+  async: bool;
+  uncurried: bool;
+  attributes: Parsetree.attributes;
+}
+
+(* determines whether a function is async and/or uncurried based on the given attributes *)
+val processFunctionAttributes : Parsetree.attributes -> functionAttributesInfo
+
+val hasAwaitAttribute : Parsetree.attributes -> bool
+
 type ifConditionKind =
   | If of Parsetree.expression
   | IfLet of Parsetree.pattern * Parsetree.expression
diff --git a/src/res_printer.ml b/src/res_printer.ml
index 79a77f8e..c1d947d4 100644
--- a/src/res_printer.ml
+++ b/src/res_printer.ml
@@ -79,6 +79,8 @@ let addBraces doc =
          Doc.rbrace;
        ])
 
+let addAsync doc = Doc.concat [Doc.text "async "; doc]
+
 let getFirstLeadingComment tbl loc =
   match Hashtbl.find tbl.CommentTable.leading loc with
   | comment :: _ -> Some comment
@@ -3093,7 +3095,7 @@ and printExpression ~customLayout (e : Parsetree.expression) cmtTbl =
     | Pexp_assert expr ->
       let rhs =
         let doc = printExpressionWithComments ~customLayout expr cmtTbl in
-        match Parens.lazyOrAssertExprRhs expr with
+        match Parens.lazyOrAssertOrAwaitExprRhs expr with
         | Parens.Parenthesized -> addParens doc
         | Braced braces -> printBraces doc expr braces
         | Nothing -> doc
@@ -3102,7 +3104,7 @@ and printExpression ~customLayout (e : Parsetree.expression) cmtTbl =
     | Pexp_lazy expr ->
       let rhs =
         let doc = printExpressionWithComments ~customLayout expr cmtTbl in
-        match Parens.lazyOrAssertExprRhs expr with
+        match Parens.lazyOrAssertOrAwaitExprRhs expr with
         | Parens.Parenthesized -> addParens doc
         | Braced braces -> printBraces doc expr braces
         | Nothing -> doc
@@ -3135,8 +3137,8 @@ and printExpression ~customLayout (e : Parsetree.expression) cmtTbl =
         cmtTbl
     | Pexp_fun _ | Pexp_newtype _ ->
       let attrsOnArrow, parameters, returnExpr = ParsetreeViewer.funExpr e in
-      let uncurried, attrs =
-        ParsetreeViewer.processUncurriedAttribute attrsOnArrow
+      let ParsetreeViewer.{async; uncurried; attributes = attrs} =
+        ParsetreeViewer.processFunctionAttributes attrsOnArrow
       in
       let returnExpr, typConstraint =
         match returnExpr.pexp_desc with
@@ -3156,7 +3158,7 @@ and printExpression ~customLayout (e : Parsetree.expression) cmtTbl =
       in
       let parametersDoc =
         printExprFunParameters ~customLayout ~inCallback:NoCallback ~uncurried
-          ~hasConstraint parameters cmtTbl
+          ~async ~hasConstraint parameters cmtTbl
       in
       let returnExprDoc =
         let optBraces, _ = ParsetreeViewer.processBracesAttr returnExpr in
@@ -3278,6 +3280,28 @@ and printExpression ~customLayout (e : Parsetree.expression) cmtTbl =
     | Pexp_poly _ -> Doc.text "Pexp_poly not impemented in printer"
     | Pexp_object _ -> Doc.text "Pexp_object not impemented in printer"
   in
+  let exprWithAwait =
+    if ParsetreeViewer.hasAwaitAttribute e.pexp_attributes then
+      let rhs =
+        match
+          Parens.lazyOrAssertOrAwaitExprRhs
+            {
+              e with
+              pexp_attributes =
+                List.filter
+                  (function
+                    | {Location.txt = "res.await" | "ns.braces"}, _ -> false
+                    | _ -> true)
+                  e.pexp_attributes;
+            }
+        with
+        | Parens.Parenthesized -> addParens printedExpression
+        | Braced braces -> printBraces printedExpression e braces
+        | Nothing -> printedExpression
+      in
+      Doc.concat [Doc.text "await "; rhs]
+    else printedExpression
+  in
   let shouldPrintItsOwnAttributes =
     match e.pexp_desc with
     | Pexp_apply _ | Pexp_fun _ | Pexp_newtype _ | Pexp_setfield _
@@ -3289,17 +3313,16 @@ and printExpression ~customLayout (e : Parsetree.expression) cmtTbl =
     | _ -> false
   in
   match e.pexp_attributes with
-  | [] -> printedExpression
+  | [] -> exprWithAwait
   | attrs when not shouldPrintItsOwnAttributes ->
     Doc.group
-      (Doc.concat
-         [printAttributes ~customLayout attrs cmtTbl; printedExpression])
-  | _ -> printedExpression
+      (Doc.concat [printAttributes ~customLayout attrs cmtTbl; exprWithAwait])
+  | _ -> exprWithAwait
 
 and printPexpFun ~customLayout ~inCallback e cmtTbl =
   let attrsOnArrow, parameters, returnExpr = ParsetreeViewer.funExpr e in
-  let uncurried, attrs =
-    ParsetreeViewer.processUncurriedAttribute attrsOnArrow
+  let ParsetreeViewer.{async; uncurried; attributes = attrs} =
+    ParsetreeViewer.processFunctionAttributes attrsOnArrow
   in
   let returnExpr, typConstraint =
     match returnExpr.pexp_desc with
@@ -3313,7 +3336,7 @@ and printPexpFun ~customLayout ~inCallback e cmtTbl =
     | _ -> (returnExpr, None)
   in
   let parametersDoc =
-    printExprFunParameters ~customLayout ~inCallback ~uncurried
+    printExprFunParameters ~customLayout ~inCallback ~async ~uncurried
       ~hasConstraint:
         (match typConstraint with
         | Some _ -> true
@@ -3513,13 +3536,13 @@ and printBinaryExpression ~customLayout (expr : Parsetree.expression) cmtTbl =
           then
             let leftPrinted = flatten ~isLhs:true left operator in
             let rightPrinted =
-              let _, rightAttrs =
+              let rightPrinteableAttrs, rightInternalAttrs =
                 ParsetreeViewer.partitionPrintableAttributes
                   right.pexp_attributes
               in
               let doc =
                 printExpressionWithComments ~customLayout
-                  {right with pexp_attributes = rightAttrs}
+                  {right with pexp_attributes = rightInternalAttrs}
                   cmtTbl
               in
               let doc =
@@ -3527,14 +3550,14 @@ and printBinaryExpression ~customLayout (expr : Parsetree.expression) cmtTbl =
                   Doc.concat [Doc.lparen; doc; Doc.rparen]
                 else doc
               in
-              let printableAttrs =
-                ParsetreeViewer.filterPrintableAttributes right.pexp_attributes
-              in
               let doc =
                 Doc.concat
-                  [printAttributes ~customLayout printableAttrs cmtTbl; doc]
+                  [
+                    printAttributes ~customLayout rightPrinteableAttrs cmtTbl;
+                    doc;
+                  ]
               in
-              match printableAttrs with
+              match rightPrinteableAttrs with
               | [] -> doc
               | _ -> addParens doc
             in
@@ -3553,22 +3576,25 @@ and printBinaryExpression ~customLayout (expr : Parsetree.expression) cmtTbl =
             in
             printComments doc cmtTbl expr.pexp_loc
           else
+            let printeableAttrs, internalAttrs =
+              ParsetreeViewer.partitionPrintableAttributes expr.pexp_attributes
+            in
             let doc =
               printExpressionWithComments ~customLayout
-                {expr with pexp_attributes = []}
+                {expr with pexp_attributes = internalAttrs}
                 cmtTbl
             in
             let doc =
               if
                 Parens.subBinaryExprOperand parentOperator operator
-                || expr.pexp_attributes <> []
+                || printeableAttrs <> []
                    && (ParsetreeViewer.isBinaryExpression expr
                       || ParsetreeViewer.isTernaryExpr expr)
               then Doc.concat [Doc.lparen; doc; Doc.rparen]
               else doc
             in
             Doc.concat
-              [printAttributes ~customLayout expr.pexp_attributes cmtTbl; doc]
+              [printAttributes ~customLayout printeableAttrs cmtTbl; doc]
         | _ -> assert false
       else
         match expr.pexp_desc with
@@ -3671,11 +3697,7 @@ and printBinaryExpression ~customLayout (expr : Parsetree.expression) cmtTbl =
                 {
                   expr with
                   pexp_attributes =
-                    List.filter
-                      (fun attr ->
-                        match attr with
-                        | {Location.txt = "ns.braces"}, _ -> false
-                        | _ -> true)
+                    ParsetreeViewer.filterPrintableAttributes
                       expr.pexp_attributes;
                 }
             with
@@ -4575,8 +4597,8 @@ and printCase ~customLayout (case : Parsetree.case) cmtTbl =
   in
   Doc.group (Doc.concat [Doc.text "| "; content])
 
-and printExprFunParameters ~customLayout ~inCallback ~uncurried ~hasConstraint
-    parameters cmtTbl =
+and printExprFunParameters ~customLayout ~inCallback ~async ~uncurried
+    ~hasConstraint parameters cmtTbl =
   match parameters with
   (* let f = _ => () *)
   | [
@@ -4589,8 +4611,11 @@ and printExprFunParameters ~customLayout ~inCallback ~uncurried ~hasConstraint
      };
   ]
     when not uncurried ->
-    let doc = if hasConstraint then Doc.text "(_)" else Doc.text "_" in
-    printComments doc cmtTbl ppat_loc
+    let any =
+      let doc = if hasConstraint then Doc.text "(_)" else Doc.text "_" in
+      printComments doc cmtTbl ppat_loc
+    in
+    if async then addAsync any else any
   (* let f = a => () *)
   | [
    ParsetreeViewer.Parameter
@@ -4604,7 +4629,8 @@ and printExprFunParameters ~customLayout ~inCallback ~uncurried ~hasConstraint
     when not uncurried ->
     let txtDoc =
       let var = printIdentLike stringLoc.txt in
-      if hasConstraint then addParens var else var
+      let var = if hasConstraint then addParens var else var in
+      if async then addAsync (Doc.concat [Doc.lparen; var; Doc.rparen]) else var
     in
     printComments txtDoc cmtTbl stringLoc.loc
   (* let f = () => () *)
@@ -4619,7 +4645,10 @@ and printExprFunParameters ~customLayout ~inCallback ~uncurried ~hasConstraint
      };
   ]
     when not uncurried ->
-    let doc = Doc.text "()" in
+    let doc =
+      let lparenRparen = Doc.text "()" in
+      if async then addAsync lparenRparen else lparenRparen
+    in
     printComments doc cmtTbl loc
   (* let f = (~greeting, ~from as hometown, ~x=?) => () *)
   | parameters ->
@@ -4628,7 +4657,10 @@ and printExprFunParameters ~customLayout ~inCallback ~uncurried ~hasConstraint
       | FitsOnOneLine -> true
       | _ -> false
     in
-    let lparen = if uncurried then Doc.text "(. " else Doc.lparen in
+    let maybeAsyncLparen =
+      let lparen = if uncurried then Doc.text "(. " else Doc.lparen in
+      if async then addAsync lparen else lparen
+    in
     let shouldHug = ParsetreeViewer.parametersShouldHug parameters in
     let printedParamaters =
       Doc.concat
@@ -4644,7 +4676,7 @@ and printExprFunParameters ~customLayout ~inCallback ~uncurried ~hasConstraint
     Doc.group
       (Doc.concat
          [
-           lparen;
+           maybeAsyncLparen;
            (if shouldHug || inCallback then printedParamaters
            else
              Doc.concat
diff --git a/src/res_token.ml b/src/res_token.ml
index 2c4f8f26..a2dceeca 100644
--- a/src/res_token.ml
+++ b/src/res_token.ml
@@ -1,6 +1,7 @@
 module Comment = Res_comment
 
 type t =
+  | Await
   | Open
   | True
   | False
@@ -111,6 +112,7 @@ let precedence = function
   | _ -> 0
 
 let toString = function
+  | Await -> "await"
   | Open -> "open"
   | True -> "true"
   | False -> "false"
@@ -210,6 +212,7 @@ let keywordTable = function
   | "and" -> And
   | "as" -> As
   | "assert" -> Assert
+  | "await" -> Await
   | "constraint" -> Constraint
   | "else" -> Else
   | "exception" -> Exception
@@ -238,9 +241,9 @@ let keywordTable = function
   [@@raises Not_found]
 
 let isKeyword = function
-  | And | As | Assert | Constraint | Else | Exception | External | False | For
-  | If | In | Include | Land | Lazy | Let | List | Lor | Module | Mutable | Of
-  | Open | Private | Rec | Switch | True | Try | Typ | When | While ->
+  | Await | And | As | Assert | Constraint | Else | Exception | External | False
+  | For | If | In | Include | Land | Lazy | Let | List | Lor | Module | Mutable
+  | Of | Open | Private | Rec | Switch | True | Try | Typ | When | While ->
     true
   | _ -> false
 
diff --git a/tests/parsing/grammar/expressions/async.res b/tests/parsing/grammar/expressions/async.res
new file mode 100644
index 00000000..b104866d
--- /dev/null
+++ b/tests/parsing/grammar/expressions/async.res
@@ -0,0 +1,29 @@
+let greetUser = async (userId) => {
+  let name = await getUserName(. userId)  
+  "Hello " ++ name ++ "!"
+}
+
+async () => 123
+
+let fetch = {
+    async (. url) => browserFetch(. url)
+}
+
+let fetch2 = {
+    async (. url) => browserFetch(. url)
+    async (. url) => browserFetch2(. url)
+}
+
+// don't parse async es6 arrow
+let async = {
+    let f = async()
+    ()->async
+    async()
+    async.async
+
+    {async: async[async]}
+
+    result->async->mapAsync(a => doStuff(a))
+}
+
+let f = isPositive ? (async (a, b) : int => a + b) : async (c, d) : int => c - d
\ No newline at end of file
diff --git a/tests/parsing/grammar/expressions/await.res b/tests/parsing/grammar/expressions/await.res
new file mode 100644
index 00000000..32a6fdf9
--- /dev/null
+++ b/tests/parsing/grammar/expressions/await.res
@@ -0,0 +1,26 @@
+await wait(2)
+
+let maybeSomeValue = switch await fetchData(url) {    
+| data => Some(data)
+| exception JsError(_) => None
+}
+
+let x = await 1 + 2
+
+let x = await wait(1) + await wait(2)
+
+let () = {
+  let response = await fetch("/users.json"); // get users list
+  let users = await response.json(); // parse JSON
+  let comments = (await (await fetch("comment.json")).json())[0];
+  Js.log2(users, comments)
+}
+
+let () = {
+    await delay(10)
+}
+
+let () = {
+    await delay(10)
+    await delay(20)
+}
\ No newline at end of file
diff --git a/tests/parsing/grammar/expressions/expected/async.res.txt b/tests/parsing/grammar/expressions/expected/async.res.txt
new file mode 100644
index 00000000..7aef8ffd
--- /dev/null
+++ b/tests/parsing/grammar/expressions/expected/async.res.txt
@@ -0,0 +1,28 @@
+let greetUser =
+  ((fun userId ->
+      ((let name = ((getUserName userId)[@res.await ][@bs ]) in
+        ({js|Hello |js} ^ name) ^ {js|!|js})
+      [@ns.braces ]))
+  [@res.async ])
+;;((fun () -> 123)[@res.async ])
+let fetch = ((fun url -> ((browserFetch url)[@bs ]))
+  [@ns.braces ][@res.async ][@bs ])
+let fetch2 =
+  (((((fun url -> ((browserFetch url)[@bs ])))
+    [@res.async ][@bs ]);
+    (((fun url -> ((browserFetch2 url)[@bs ])))
+    [@res.async ][@bs ]))
+  [@ns.braces ])
+let async =
+  ((let f = async () in
+    () |. async;
+    async ();
+    async.async;
+    { async = (async.(async)) };
+    (result |. async) |. (mapAsync (fun a -> doStuff a)))
+  [@ns.braces ])
+let f =
+  ((if isPositive
+    then ((fun a -> fun b -> (a + b : int))[@res.async ])
+    else (((fun c -> fun d -> (c - d : int)))[@res.async ]))
+  [@ns.ternary ])
\ No newline at end of file
diff --git a/tests/parsing/grammar/expressions/expected/await.res.txt b/tests/parsing/grammar/expressions/expected/await.res.txt
new file mode 100644
index 00000000..8f8d9f70
--- /dev/null
+++ b/tests/parsing/grammar/expressions/expected/await.res.txt
@@ -0,0 +1,18 @@
+;;((wait 2)[@res.await ])
+let maybeSomeValue =
+  match ((fetchData url)[@res.await ]) with
+  | data -> Some data
+  | exception JsError _ -> None
+let x = ((1)[@res.await ]) + 2
+let x = ((wait 1)[@res.await ]) + ((wait 2)[@res.await ])
+let () =
+  ((let response = ((fetch {js|/users.json|js})[@res.await ]) in
+    let users = ((response.json ())[@res.await ]) in
+    let comments =
+      ((((fetch {js|comment.json|js})[@res.await ]).json ())
+      [@res.await ]).(0) in
+    Js.log2 users comments)
+  [@ns.braces ])
+let () = ((delay 10)[@ns.braces ][@res.await ])
+let () = ((((delay 10)[@res.await ]); ((delay 20)[@res.await ]))
+  [@ns.braces ])
\ No newline at end of file
diff --git a/tests/printer/expr/asyncAwait.res b/tests/printer/expr/asyncAwait.res
new file mode 100644
index 00000000..4265a891
--- /dev/null
+++ b/tests/printer/expr/asyncAwait.res
@@ -0,0 +1,83 @@
+let sequentialAwait = async () => {
+  let result1 = await paused("first")
+  nodeJsAssert.equal(result1, "first")
+  
+  let result2 = await paused("second")
+  nodeJsAssert.equal(result2, "second")
+}
+
+let f = async () => ()
+let f = async (.) => ()
+let f = async f => f()
+let f = async (a, b) => a + b
+let f = async (. a, b) => a + b
+
+
+let maybeSomeValue = switch await fetchData(url) {    
+| data => Some(data)
+| exception JsError(_) => None
+}
+
+(await f)(a, b) 
+-(await f)
+await 1 + await 2
+
+lazy (await f())
+assert (await f())
+
+(await f).json()
+
+user.data = await fetch()
+
+<Navbar promise={await gc()}>{await weirdReactSuspenseApi}</Navbar>
+
+let inBinaryExpression = await x->Js.Promise.resolve + 1
+let inBinaryExpression = await x->Js.Promise.resolve + await y->Js.Promise.resolve
+
+let withCallback = async (. ()) => {
+    async (. x) => await (x->Js.promise.resolve) + 1
+}
+
+let () = await (await fetch(url))->(await resolve)
+
+let _ = await (1 + 1)
+let _ = await 1 + 1
+let _ = await (-1)
+let _ = await - 1
+let _ = await !ref 
+let _ = await f
+let _ = await %extension 
+let _ = await "test"
+let _ = await ((a, b) => a + b)
+let _ = await (async (a, b) => a + b)
+let _ = await (switch x { | A => () | B => ()})
+let _ = await [1, 2, 3]
+let _ = await (1, 2, 3)
+let _ = await {name: "Steve", age: 32}
+let _ = await (user.name = "Steve")
+let _ = await (if 20 { true } else {false})
+let _ = await (condition() ? true : false)
+let _ = await f(x)
+let _ = await f(. x)
+let _ = await (f(x) : Js.Promise.t<unit>)
+let _ = await (while true { infiniteLoop() })
+let _ = await (try ok() catch { | _  =>  logError() })
+let _ = await (for i in 0 to 10 { sideEffect()})
+let _ = await (lazy x)
+let _ = await (assert x)
+let _ = await promises[0]
+let _ = await promises["resolved"]
+let _ = await (promises["resolved"] = sideEffect())
+let _ = await (@attr expr)
+let _ = await module(Foo)
+let _ = await module(Foo: Bar)
+let _ = await Promise
+let _ = await Promise(status)
+
+// braces are being dropped, because the ast only has space to record braces surrounding the await
+let _ = await {x}
+// here braces stay, because of precedence
+let _ = await {
+    let x = 1
+    Js.Promise.resolve(x)
+}
\ No newline at end of file
diff --git a/tests/printer/expr/expected/asyncAwait.res.txt b/tests/printer/expr/expected/asyncAwait.res.txt
new file mode 100644
index 00000000..7a8642c4
--- /dev/null
+++ b/tests/printer/expr/expected/asyncAwait.res.txt
@@ -0,0 +1,105 @@
+let sequentialAwait = async () => {
+  let result1 = await paused("first")
+  nodeJsAssert.equal(result1, "first")
+
+  let result2 = await paused("second")
+  nodeJsAssert.equal(result2, "second")
+}
+
+let f = async () => ()
+let f = async (. ()) => ()
+let f = async (f) => f()
+let f = async (a, b) => a + b
+let f = async (. a, b) => a + b
+
+let maybeSomeValue = switch await fetchData(url) {
+| data => Some(data)
+| exception JsError(_) => None
+}
+
+(await f)(a, b)
+-(await f)
+(await 1) + (await 2)
+
+lazy (await f())
+assert (await f())
+
+(await f).json()
+
+user.data = await fetch()
+
+<Navbar promise={await gc()}> {await weirdReactSuspenseApi} </Navbar>
+
+let inBinaryExpression = (await x)->Js.Promise.resolve + 1
+let inBinaryExpression = (await x)->Js.Promise.resolve + (await y)->Js.Promise.resolve
+
+let withCallback = async (. ()) => {
+  async (. x) => await (x->Js.promise.resolve) + 1
+}
+
+let () = (await fetch(url))->(await resolve)
+
+let _ = await (1 + 1)
+let _ = (await 1) + 1
+let _ = await -1
+let _ = await -1
+let _ = await !ref
+let _ = await f
+let _ = await %extension
+let _ = await "test"
+let _ = await ((a, b) => a + b)
+let _ = await (async (a, b) => a + b)
+let _ = await (
+  switch x {
+  | A => ()
+  | B => ()
+  }
+)
+let _ = await [1, 2, 3]
+let _ = await (1, 2, 3)
+let _ = await {name: "Steve", age: 32}
+let _ = await (user.name = "Steve")
+let _ = await (
+  if 20 {
+    true
+  } else {
+    false
+  }
+)
+let _ = await (condition() ? true : false)
+let _ = await f(x)
+let _ = await f(. x)
+let _ = (await (f(x): Js.Promise.t<unit>))
+let _ = await (
+  while true {
+    infiniteLoop()
+  }
+)
+let _ = await (
+  try ok() catch {
+  | _ => logError()
+  }
+)
+let _ = await (
+  for i in 0 to 10 {
+    sideEffect()
+  }
+)
+let _ = await (lazy x)
+let _ = await (assert x)
+let _ = await promises[0]
+let _ = await promises["resolved"]
+let _ = await promises["resolved"] = sideEffect()
+let _ = @attr await (expr)
+let _ = await module(Foo)
+let _ = await module(Foo: Bar)
+let _ = await Promise
+let _ = await Promise(status)
+
+// braces are being dropped, because the ast only has space to record braces surrounding the await
+let _ = await x
+// here braces stay, because of precedence
+let _ = await {
+  let x = 1
+  Js.Promise.resolve(x)
+}