diff --git a/modules/cli/src/main/scala/scala/cli/commands/repl/Repl.scala b/modules/cli/src/main/scala/scala/cli/commands/repl/Repl.scala
index fd69915a56..ea0dc10186 100644
--- a/modules/cli/src/main/scala/scala/cli/commands/repl/Repl.scala
+++ b/modules/cli/src/main/scala/scala/cli/commands/repl/Repl.scala
@@ -394,23 +394,25 @@ object Repl extends ScalaCommand[ReplOptions] with BuildCommandHelpers {
       if (dryRun)
         logger.message("Dry run, not running REPL.")
       else {
+        val isAmmonite = replArtifacts.replMainClass.startsWith("ammonite")
         val depClassPathArgs: Seq[String] =
-          if replArtifacts.depsClassPath.nonEmpty && !replArtifacts.replMainClass.startsWith(
-              "ammonite"
-            )
-          then
+          if replArtifacts.depsClassPath.nonEmpty && !isAmmonite then
             Seq(
               "-classpath",
-              replArtifacts.depsClassPath.map(_.toString).mkString(File.pathSeparator)
+              (mainJarsOrClassDirs ++ replArtifacts.depsClassPath)
+                .map(_.toString).mkString(File.pathSeparator)
             )
           else Nil
+        val replLauncherClasspath =
+          if isAmmonite then mainJarsOrClassDirs ++ replArtifacts.replClassPath
+          else replArtifacts.replClassPath
         val retCode = Runner.runJvm(
           javaCommand = options.javaHome().value.javaCommand,
           javaArgs = scalapyJavaOpts ++
             replArtifacts.replJavaOpts ++
             options.javaOptions.javaOpts.toSeq.map(_.value.value) ++
             extraProps.toVector.sorted.map { case (k, v) => s"-D$k=$v" },
-          classPath = mainJarsOrClassDirs ++ replArtifacts.replClassPath,
+          classPath = replLauncherClasspath,
           mainClass = replArtifacts.replMainClass,
           args = maybeAdaptForWindows(depClassPathArgs ++ replArgs),
           logger = logger,
diff --git a/modules/integration/src/test/scala/scala/cli/integration/ReplTestDefinitions.scala b/modules/integration/src/test/scala/scala/cli/integration/ReplTestDefinitions.scala
index 3bd1f0ee29..3c0e2c97dd 100644
--- a/modules/integration/src/test/scala/scala/cli/integration/ReplTestDefinitions.scala
+++ b/modules/integration/src/test/scala/scala/cli/integration/ReplTestDefinitions.scala
@@ -7,7 +7,7 @@ import scala.util.Properties
 
 abstract class ReplTestDefinitions extends ScalaCliSuite with TestScalaVersionArgs {
   _: TestScalaVersion =>
-  private lazy val extraOptions = scalaVersionArgs ++ TestUtil.extraOptions
+  protected lazy val extraOptions: Seq[String] = scalaVersionArgs ++ TestUtil.extraOptions
 
   private val retrieveScalaVersionCode = if (actualScalaVersion.startsWith("2."))
     "scala.util.Properties.versionNumberString"
diff --git a/modules/integration/src/test/scala/scala/cli/integration/ReplTests3StableDefinitions.scala b/modules/integration/src/test/scala/scala/cli/integration/ReplTests3StableDefinitions.scala
index 66223190fa..5282286092 100644
--- a/modules/integration/src/test/scala/scala/cli/integration/ReplTests3StableDefinitions.scala
+++ b/modules/integration/src/test/scala/scala/cli/integration/ReplTests3StableDefinitions.scala
@@ -1,5 +1,9 @@
 package scala.cli.integration
 
+import com.eed3si9n.expecty.Expecty.expect
+
+import scala.util.Properties
+
 trait ReplTests3StableDefinitions { _: ReplTestDefinitions =>
   if (!actualScalaVersion.equals(actualMaxAmmoniteScalaVersion)) {
     lazy val defaultScalaVersionString =
@@ -16,4 +20,31 @@ trait ReplTests3StableDefinitions { _: ReplTestDefinitions =>
       ammoniteTestScope(useMaxAmmoniteScalaVersion = false)
     }
   }
+
+  test("https://github.com/scala/scala3/issues/21229") {
+    TestInputs(
+      os.rel / "Pprint.scala" ->
+        """//> using dep "com.lihaoyi::pprint::0.9.0"
+          |package stuff
+          |import scala.quoted.*
+          |def foo = pprint(1)
+          |inline def bar = pprint(1)
+          |inline def baz = ${ bazImpl }
+          |def bazImpl(using Quotes) = '{ pprint(1) }
+          |""".stripMargin
+    ).fromRoot { root =>
+      val ammArgs = Seq("-c", "println(stuff.baz)")
+        .map {
+          if (Properties.isWin)
+            a => if (a.contains(" ")) "\"" + a.replace("\"", "\\\"") + "\"" else a
+          else
+            identity
+        }
+        .flatMap(arg => Seq("--ammonite-arg", arg))
+      // FIXME: test this on standard Scala 3 REPL, rather than just Ammonite
+      val res = os.proc(TestUtil.cli, "repl", ".", "--power", "--amm", ammArgs, extraOptions)
+        .call(cwd = root)
+      expect(res.out.trim().nonEmpty)
+    }
+  }
 }