diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
index 254fa10ece8..ebecbcf4df4 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
@@ -10550,6 +10550,22 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
             }
         }
 
+        @Nested
+        @TestMetadata("compiler/testData/diagnostics/tests/external")
+        @TestDataPath("$PROJECT_ROOT")
+        public class External {
+            @Test
+            public void testAllFilesPresentInExternal() throws Exception {
+                KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/external"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.fir\\.kts?$"), true);
+            }
+
+            @Test
+            @TestMetadata("noExternalModifierInheritance.kt")
+            public void testNoExternalModifierInheritance() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt");
+            }
+        }
+
         @Nested
         @TestMetadata("compiler/testData/diagnostics/tests/funInterface")
         @TestDataPath("$PROJECT_ROOT")
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
index 64f6d47efdf..21eb59d385a 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
@@ -10550,6 +10550,22 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
             }
         }
 
+        @Nested
+        @TestMetadata("compiler/testData/diagnostics/tests/external")
+        @TestDataPath("$PROJECT_ROOT")
+        public class External {
+            @Test
+            public void testAllFilesPresentInExternal() throws Exception {
+                KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/external"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.fir\\.kts?$"), true);
+            }
+
+            @Test
+            @TestMetadata("noExternalModifierInheritance.kt")
+            public void testNoExternalModifierInheritance() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt");
+            }
+        }
+
         @Nested
         @TestMetadata("compiler/testData/diagnostics/tests/funInterface")
         @TestDataPath("$PROJECT_ROOT")
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java
index 50cf1150cfe..2c52346ed74 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java
@@ -10550,6 +10550,22 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
             }
         }
 
+        @Nested
+        @TestMetadata("compiler/testData/diagnostics/tests/external")
+        @TestDataPath("$PROJECT_ROOT")
+        public class External {
+            @Test
+            public void testAllFilesPresentInExternal() throws Exception {
+                KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/external"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.fir\\.kts?$"), true);
+            }
+
+            @Test
+            @TestMetadata("noExternalModifierInheritance.kt")
+            public void testNoExternalModifierInheritance() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt");
+            }
+        }
+
         @Nested
         @TestMetadata("compiler/testData/diagnostics/tests/funInterface")
         @TestDataPath("$PROJECT_ROOT")
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirStatusResolver.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirStatusResolver.kt
index a262f8c303a..09e0c077c18 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirStatusResolver.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirStatusResolver.kt
@@ -40,6 +40,7 @@ class FirStatusResolver(
             FirDeclarationStatusImpl.Modifier.CONST,
             FirDeclarationStatusImpl.Modifier.LATEINIT,
             FirDeclarationStatusImpl.Modifier.TAILREC,
+            FirDeclarationStatusImpl.Modifier.EXTERNAL,
         )
 
         private val MODIFIERS_FROM_OVERRIDDEN: List<FirDeclarationStatusImpl.Modifier> =
diff --git a/compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt b/compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt
new file mode 100644
index 00000000000..24701f8334a
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt
@@ -0,0 +1,10 @@
+// FIR_IDENTICAL
+open class A {
+    open external fun foo()
+}
+
+class B : A() {
+    override fun foo() {
+        super.foo()
+    }
+}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.txt b/compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.txt
new file mode 100644
index 00000000000..0f4e0d7cf0e
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.txt
@@ -0,0 +1,17 @@
+package
+
+public open class A {
+    public constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open external fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class B : A {
+    public constructor B()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
index 971ebf4c269..d7112b05409 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
@@ -10556,6 +10556,22 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
             }
         }
 
+        @Nested
+        @TestMetadata("compiler/testData/diagnostics/tests/external")
+        @TestDataPath("$PROJECT_ROOT")
+        public class External {
+            @Test
+            public void testAllFilesPresentInExternal() throws Exception {
+                KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/external"), Pattern.compile("^(.*)\\.kts?$"), Pattern.compile("^(.+)\\.fir\\.kts?$"), true);
+            }
+
+            @Test
+            @TestMetadata("noExternalModifierInheritance.kt")
+            public void testNoExternalModifierInheritance() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt");
+            }
+        }
+
         @Nested
         @TestMetadata("compiler/testData/diagnostics/tests/funInterface")
         @TestDataPath("$PROJECT_ROOT")