diff --git a/kotlin-native/backend.native/tests/interop/objc/kt55938/lib.kt b/kotlin-native/backend.native/tests/interop/objc/kt55938/lib.kt
index 7cf158ec6c0..56025b3bf2d 100644
--- a/kotlin-native/backend.native/tests/interop/objc/kt55938/lib.kt
+++ b/kotlin-native/backend.native/tests/interop/objc/kt55938/lib.kt
@@ -2,6 +2,7 @@
  * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
+@file:OptIn(kotlinx.cinterop.ExperimentalForeignApi::class)
 
 package kt55938lib
 
diff --git a/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractNativeCInteropKT39120Test.kt b/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractNativeCInteropKT39120Test.kt
index a2b43515ea7..3a1d37a95d9 100644
--- a/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractNativeCInteropKT39120Test.kt
+++ b/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractNativeCInteropKT39120Test.kt
@@ -79,7 +79,7 @@ abstract class AbstractNativeCInteropKT39120Test : AbstractNativeCInteropBaseTes
     private fun filterContentsOutput(contents: String, pattern: String) =
         contents.split("\n").filter {
             it.contains(Regex(pattern))
-        }.joinToString(separator = "\n")
+        }.joinToString(separator = "\n").replace("@ExperimentalForeignApi ", "")
 
     private fun createTestCaseNoTestRun(module: TestModule.Exclusive, compilerArgs: TestCompilerArgs) = TestCase(
         id = TestCaseId.Named(module.name),
diff --git a/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractNativeCInteropTest.kt b/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractNativeCInteropTest.kt
index 43d0f45790d..cec192dd4a2 100644
--- a/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractNativeCInteropTest.kt
+++ b/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractNativeCInteropTest.kt
@@ -49,6 +49,12 @@ abstract class AbstractNativeCInteropTest : AbstractNativeCInteropBaseTest() {
 
     abstract val defFileName: String
 
+    // All declarations generated by cinterop now have ExperimentalForeignApi annotations.
+    // There is no sense in cluttering every test expected data with it, so we simply ignore it
+    // in the actual data by default:
+    open val ignoreExperimentalForeignApi: Boolean
+        get() = true
+
     @Synchronized
     protected fun runTest(@TestDataFile testPath: String) {
         // FIXME: check the following failures under Android with -fmodules
@@ -88,6 +94,13 @@ abstract class AbstractNativeCInteropTest : AbstractNativeCInteropBaseTest() {
             }
         } else {
             val klibContents = testCompilationResult.assertSuccess().resultingArtifact.getContents(kotlinNativeClassLoader.classLoader)
+                .let {
+                    if (ignoreExperimentalForeignApi) {
+                        it.replace("@ExperimentalForeignApi ", "")
+                    } else {
+                        it
+                    }
+                }
             val expectedContents = goldenFile.readText()
             assertEquals(StringUtilRt.convertLineSeparators(expectedContents), StringUtilRt.convertLineSeparators(klibContents)) {
                 "Test failed. CInterop compilation result was: $testCompilationResult"
diff --git a/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/LinkerOutputTestKT55578.kt b/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/LinkerOutputTestKT55578.kt
index adab8f547bf..09abaf6d286 100644
--- a/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/LinkerOutputTestKT55578.kt
+++ b/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/LinkerOutputTestKT55578.kt
@@ -20,6 +20,8 @@ import kotlin.test.assertTrue
 @TestDataPath("\$PROJECT_ROOT")
 @EnforcedProperty(ClassLevelProperty.COMPILER_OUTPUT_INTERCEPTOR, "NONE")
 class LinkerOutputTestKT55578 : AbstractNativeLinkerOutputTest() {
+    private val defaultCompilerArguments = listOf("-opt-in=kotlinx.cinterop.ExperimentalForeignApi")
+
     private val testDir = File("native/native.tests/testData/CInterop/KT-55578/")
 
     private val hint1 = "<<HINT1>>"
@@ -166,7 +168,11 @@ class LinkerOutputTestKT55578 : AbstractNativeLinkerOutputTest() {
             files += TestFile.createCommitted(file, this)
         }
 
-        return compileToExecutable(module, libraries.asList().map { it.asLibraryDependency() }, extraArgs)
+        return compileToExecutable(
+            module,
+            libraries.asList().map { it.asLibraryDependency() },
+            defaultCompilerArguments + extraArgs
+        )
     }
 
     private fun compileKlib(defFile: File, sourceFile: File? = null, extraArgs: List<String> = emptyList()): KLIB {