diff --git a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/webpack/KotlinWebpack.kt b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/webpack/KotlinWebpack.kt
index ece65c7ee5c..894ed351795 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/webpack/KotlinWebpack.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/webpack/KotlinWebpack.kt
@@ -119,7 +119,7 @@ constructor(
     @get:Internal
     val entry: Provider<RegularFile>
         get() = inputFilesDirectory.map {
-            it.file(entryModuleName.get() + ".js")
+            it.file(entryModuleName.get() + if (platformType == KotlinPlatformType.wasm) ".mjs" else ".js")
         }
 
     init {