diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 56b0b7457f83..046153a8d54b 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -93,7 +93,7 @@ jobs:
 
       - name: Test
         run: |
-          ./project/scripts/sbt ";dotty-bootstrapped/compile ;dotty-bootstrapped/test;sjsSandbox/run;sjsSandbox/test;sjsJUnitTests/test;sjsCompilerTests/test ;configureIDE"
+          ./project/scripts/sbt ";dotty-bootstrapped/compile ;dotty-bootstrapped/test;sjsSandbox/run;sjsSandbox/test;sjsJUnitTests/test;sjsCompilerTests/test ;scala2-interop-tests/scripted ;configureIDE"
           ./project/scripts/bootstrapCmdTests
 
 
diff --git a/build.sbt b/build.sbt
index 28559cb1c4a9..eee30e51036f 100644
--- a/build.sbt
+++ b/build.sbt
@@ -27,6 +27,7 @@ val `scala-reflect` = Build.`scala-reflect`
 val scalap = Build.scalap
 val dist = Build.dist
 val `community-build` = Build.`community-build`
+val `scala2-interop-tests` = Build.`scala2-interop-tests`
 
 val sjsSandbox = Build.sjsSandbox
 val sjsJUnitTests = Build.sjsJUnitTests
diff --git a/project/Build.scala b/project/Build.scala
index 10a29512152e..76fd7f5d4378 100644
--- a/project/Build.scala
+++ b/project/Build.scala
@@ -1126,6 +1126,39 @@ object Build {
       libraryDependencies := Seq("org.scala-lang" % "scalap" % stdlibVersion(Bootstrapped))
     )
 
+  lazy val `scala2-interop-tests` = project.in(file("tests/scala2-interop")).
+    enablePlugins(SbtPlugin).
+    settings(commonSettings).
+    settings(
+      sbtTestDirectory := baseDirectory.value / "sbt-test",
+      scriptedLaunchOpts ++= Seq(
+        "-Dplugin.version=" + sbtDottyVersion,
+        "-Dplugin.scalaVersion=" + dottyVersion,
+        "-Dplugin.scala2Version=" + stdlibVersion(Bootstrapped),
+        "-Dsbt.boot.directory=" + ((baseDirectory in ThisBuild).value / ".sbt-scripted").getAbsolutePath // Workaround sbt/sbt#3469
+      ),
+      // Pass along ivy home and repositories settings to sbt instances run from the tests
+      scriptedLaunchOpts ++= {
+        val repositoryPath = (io.Path.userHome / ".sbt" / "repositories").absolutePath
+        s"-Dsbt.repository.config=$repositoryPath" ::
+        ivyPaths.value.ivyHome.map("-Dsbt.ivy.home=" + _.getAbsolutePath).toList
+      },
+      scriptedBufferLog := true,
+      scripted := scripted.dependsOn(
+        publishLocal in `dotty-sbt-bridge`,
+        publishLocal in `dotty-interfaces`,
+        publishLocal in `dotty-compiler-bootstrapped`,
+        publishLocal in `dotty-library-bootstrapped`,
+        publishLocal in `dotty-library-bootstrappedJS`,
+        publishLocal in `tasty-core-bootstrapped`,
+        publishLocal in `dotty-tasty-inspector`,
+        publishLocal in `scala-library`,
+        publishLocal in `scala-reflect`,
+        publishLocal in `dotty-doc-bootstrapped`,
+        publishLocal in `dotty-bootstrapped`,
+        publishLocal in `sbt-dotty`
+      ).evaluated
+    )
 
   // sbt plugin to use Dotty in your own build, see
   // https://github.com/lampepfl/dotty-example-project for usage.
diff --git a/sbt-dotty/sbt-test/scala2-compat/akka/build.sbt b/tests/scala2-interop/sbt-test/3rdparty/akka/build.sbt
similarity index 100%
rename from sbt-dotty/sbt-test/scala2-compat/akka/build.sbt
rename to tests/scala2-interop/sbt-test/3rdparty/akka/build.sbt
diff --git a/sbt-dotty/sbt-test/scala2-compat/akka/i3100.scala b/tests/scala2-interop/sbt-test/3rdparty/akka/i3100.scala
similarity index 100%
rename from sbt-dotty/sbt-test/scala2-compat/akka/i3100.scala
rename to tests/scala2-interop/sbt-test/3rdparty/akka/i3100.scala
diff --git a/sbt-dotty/sbt-test/scala2-compat/akka/project/plugins.sbt b/tests/scala2-interop/sbt-test/3rdparty/akka/project/plugins.sbt
similarity index 100%
rename from sbt-dotty/sbt-test/scala2-compat/akka/project/plugins.sbt
rename to tests/scala2-interop/sbt-test/3rdparty/akka/project/plugins.sbt
diff --git a/sbt-dotty/sbt-test/scala2-compat/akka/test b/tests/scala2-interop/sbt-test/3rdparty/akka/test
similarity index 100%
rename from sbt-dotty/sbt-test/scala2-compat/akka/test
rename to tests/scala2-interop/sbt-test/3rdparty/akka/test
diff --git a/sbt-dotty/sbt-test/scala2-compat/eff/build.sbt b/tests/scala2-interop/sbt-test/3rdparty/eff/build.sbt
similarity index 100%
rename from sbt-dotty/sbt-test/scala2-compat/eff/build.sbt
rename to tests/scala2-interop/sbt-test/3rdparty/eff/build.sbt
diff --git a/sbt-dotty/sbt-test/scala2-compat/eff/i6484.scala b/tests/scala2-interop/sbt-test/3rdparty/eff/i6484.scala
similarity index 100%
rename from sbt-dotty/sbt-test/scala2-compat/eff/i6484.scala
rename to tests/scala2-interop/sbt-test/3rdparty/eff/i6484.scala
diff --git a/sbt-dotty/sbt-test/scala2-compat/eff/project/plugins.sbt b/tests/scala2-interop/sbt-test/3rdparty/eff/project/plugins.sbt
similarity index 100%
rename from sbt-dotty/sbt-test/scala2-compat/eff/project/plugins.sbt
rename to tests/scala2-interop/sbt-test/3rdparty/eff/project/plugins.sbt
diff --git a/sbt-dotty/sbt-test/scala2-compat/eff/test b/tests/scala2-interop/sbt-test/3rdparty/eff/test
similarity index 100%
rename from sbt-dotty/sbt-test/scala2-compat/eff/test
rename to tests/scala2-interop/sbt-test/3rdparty/eff/test
diff --git a/tests/scala2-interop/sbt-test/3rdparty/finagle/build.sbt b/tests/scala2-interop/sbt-test/3rdparty/finagle/build.sbt
new file mode 100644
index 000000000000..a3c28b3d6943
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/3rdparty/finagle/build.sbt
@@ -0,0 +1,4 @@
+scalaVersion := sys.props("plugin.scalaVersion")
+
+libraryDependencies +=
+  ("com.twitter" %% "finagle-core" % "20.9.0").withDottyCompat(scalaVersion.value)
diff --git a/tests/scala2-interop/sbt-test/3rdparty/finagle/i9916.scala b/tests/scala2-interop/sbt-test/3rdparty/finagle/i9916.scala
new file mode 100644
index 000000000000..7c692f529428
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/3rdparty/finagle/i9916.scala
@@ -0,0 +1,10 @@
+import com.twitter.finagle.Stack
+import com.twitter.finagle.liveness.FailureAccrualFactory
+
+trait T {
+  def p: FailureAccrualFactory.Param
+}
+
+class A {
+  val t = Stack.Param[FailureAccrualFactory.Param](FailureAccrualFactory.Param(???))
+}
diff --git a/tests/scala2-interop/sbt-test/3rdparty/finagle/pending b/tests/scala2-interop/sbt-test/3rdparty/finagle/pending
new file mode 100644
index 000000000000..5df2af1f3956
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/3rdparty/finagle/pending
@@ -0,0 +1 @@
+> compile
diff --git a/tests/scala2-interop/sbt-test/3rdparty/finagle/project/plugins.sbt b/tests/scala2-interop/sbt-test/3rdparty/finagle/project/plugins.sbt
new file mode 100644
index 000000000000..c17caab2d98c
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/3rdparty/finagle/project/plugins.sbt
@@ -0,0 +1 @@
+addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % sys.props("plugin.version"))
diff --git a/tests/scala2-interop/sbt-test/pos/i9916a/build.sbt b/tests/scala2-interop/sbt-test/pos/i9916a/build.sbt
new file mode 100644
index 000000000000..32ec1fc1cc63
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/pos/i9916a/build.sbt
@@ -0,0 +1,15 @@
+val scala3Version = sys.props("plugin.scalaVersion")
+val scala2Version = sys.props("plugin.scala2Version")
+
+lazy val `i9916a-lib` = (project in file ("lib"))
+  .settings(scalaVersion := scala2Version)
+
+lazy val `i9916a-test` = (project in file ("main"))
+  .dependsOn(`i9916a-lib`)
+  .settings(
+    scalaVersion := scala3Version,
+    // https://github.com/sbt/sbt/issues/5369
+    projectDependencies := {
+      projectDependencies.value.map(_.withDottyCompat(scalaVersion.value))
+    }
+  )
diff --git a/tests/scala2-interop/sbt-test/pos/i9916a/lib/i9916a-lib.scala b/tests/scala2-interop/sbt-test/pos/i9916a/lib/i9916a-lib.scala
new file mode 100644
index 000000000000..44882333a2f5
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/pos/i9916a/lib/i9916a-lib.scala
@@ -0,0 +1,7 @@
+package i9916a
+
+object Lib {
+  trait P
+  object P
+  def P(x: Int): P = ???
+}
diff --git a/tests/scala2-interop/sbt-test/pos/i9916a/main/i9916a-test.scala b/tests/scala2-interop/sbt-test/pos/i9916a/main/i9916a-test.scala
new file mode 100644
index 000000000000..1b10c3504ca7
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/pos/i9916a/main/i9916a-test.scala
@@ -0,0 +1,5 @@
+import i9916a.Lib
+
+trait Test {
+  def foo: Lib.P
+}
diff --git a/tests/scala2-interop/sbt-test/pos/i9916a/pending b/tests/scala2-interop/sbt-test/pos/i9916a/pending
new file mode 100644
index 000000000000..2a848354ed12
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/pos/i9916a/pending
@@ -0,0 +1 @@
+> i9916a-test/compile
diff --git a/tests/scala2-interop/sbt-test/pos/i9916a/project/plugins.sbt b/tests/scala2-interop/sbt-test/pos/i9916a/project/plugins.sbt
new file mode 100644
index 000000000000..c17caab2d98c
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/pos/i9916a/project/plugins.sbt
@@ -0,0 +1 @@
+addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % sys.props("plugin.version"))
diff --git a/tests/scala2-interop/sbt-test/pos/i9916b/build.sbt b/tests/scala2-interop/sbt-test/pos/i9916b/build.sbt
new file mode 100644
index 000000000000..f789fd0860b8
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/pos/i9916b/build.sbt
@@ -0,0 +1,15 @@
+val scala3Version = sys.props("plugin.scalaVersion")
+val scala2Version = sys.props("plugin.scala2Version")
+
+lazy val `i9916b-lib` = (project in file ("lib"))
+  .settings(scalaVersion := scala2Version)
+
+lazy val `i9916b-test` = (project in file ("main"))
+  .dependsOn(`i9916b-lib`)
+  .settings(
+    scalaVersion := scala3Version,
+    // https://github.com/sbt/sbt/issues/5369
+    projectDependencies := {
+      projectDependencies.value.map(_.withDottyCompat(scalaVersion.value))
+    }
+  )
diff --git a/tests/scala2-interop/sbt-test/pos/i9916b/lib/i9916b-lib.scala b/tests/scala2-interop/sbt-test/pos/i9916b/lib/i9916b-lib.scala
new file mode 100644
index 000000000000..0ce017246f86
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/pos/i9916b/lib/i9916b-lib.scala
@@ -0,0 +1,7 @@
+package i9916b
+
+trait T {
+  class A
+  object A
+  def A(x: Int): Unit = ???
+}
diff --git a/tests/scala2-interop/sbt-test/pos/i9916b/main/i9916b-test.scala b/tests/scala2-interop/sbt-test/pos/i9916b/main/i9916b-test.scala
new file mode 100644
index 000000000000..fb702d1a8617
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/pos/i9916b/main/i9916b-test.scala
@@ -0,0 +1,5 @@
+import i9916b.T
+
+trait Test {
+  def foo: T
+}
diff --git a/tests/scala2-interop/sbt-test/pos/i9916b/project/plugins.sbt b/tests/scala2-interop/sbt-test/pos/i9916b/project/plugins.sbt
new file mode 100644
index 000000000000..c17caab2d98c
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/pos/i9916b/project/plugins.sbt
@@ -0,0 +1 @@
+addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % sys.props("plugin.version"))
diff --git a/tests/scala2-interop/sbt-test/pos/i9916b/test b/tests/scala2-interop/sbt-test/pos/i9916b/test
new file mode 100644
index 000000000000..064736132510
--- /dev/null
+++ b/tests/scala2-interop/sbt-test/pos/i9916b/test
@@ -0,0 +1 @@
+> i9916b-test/compile