Index: clang/lib/CodeGen/CGVTables.cpp
===================================================================
--- clang/lib/CodeGen/CGVTables.cpp
+++ clang/lib/CodeGen/CGVTables.cpp
@@ -1174,7 +1174,24 @@
 
   // Otherwise, if we don't have a definition of the key function, the
   // vtable must be defined somewhere else.
-  return !keyFunction->hasBody();
+  if (!keyFunction->hasBody())
+    return true;
+
+  // If the non-inline key function comes from another module unit, the vtable
+  // must be defined there.
+  if (keyFunction->isInAnotherModuleUnit()) {
+    bool AllowInlineKeyFunctions =
+        CGM.getContext().getTargetInfo().getCXXABI().canKeyFunctionBeInline();
+    const FunctionDecl *Def;
+    bool InlineKeyFunctions = AllowInlineKeyFunctions &&
+                              keyFunction->hasBody(Def) &&
+                              Def->isInlineSpecified();
+
+    if (!InlineKeyFunctions)
+      return true;
+  }
+
+  return false;
 }
 
 /// Given that we're currently at the end of the translation unit, and
Index: clang/test/CodeGenCXX/modules-vtable.cppm
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/modules-vtable.cppm
@@ -0,0 +1,60 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: cd %t
+//
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 -emit-module-interface \
+// RUN:     %t/Mod.cppm -o %t/Mod.pcm
+//
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 %t/Mod.pcm \
+// RUN:     -emit-llvm -o - | FileCheck %t/Mod.cppm
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 -fmodule-file=Mod=%t/Mod.pcm \
+// RUN:     %t/Use.cpp  -emit-llvm -o - | FileCheck %t/Use.cpp
+//
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 -emit-module-interface \
+// RUN:     %t/Mod.cppm -o %t/Mod.pcm -DKEY_FUNCTION_INLINE
+//
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 %t/Mod.pcm \
+// RUN:     -emit-llvm -o - | FileCheck %t/Mod.cppm -check-prefix=CHECK-INLINE
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 -fmodule-file=Mod=%t/Mod.pcm \
+// RUN:     %t/Use.cpp  -emit-llvm -o - | FileCheck %t/Use.cpp -check-prefix=CHECK-INLINE
+
+//--- Mod.cppm
+export module Mod;
+
+export class Base {
+public:
+    virtual ~Base();
+};
+#ifdef KEY_FUNCTION_INLINE
+inline
+#endif
+Base::~Base() {}
+
+// CHECK: @_ZTVW3Mod4Base = unnamed_addr constant
+// CHECK: @_ZTSW3Mod4Base = constant
+// CHECK: @_ZTIW3Mod4Base = constant
+
+// CHECK-INLINE: @_ZTVW3Mod4Base = linkonce_odr unnamed_addr constant
+// CHECK-INLINE: @_ZTSW3Mod4Base = linkonce_odr constant
+// CHECK-INLINE: @_ZTIW3Mod4Base = linkonce_odr constant
+
+module :private;
+int private_use() {
+    Base base;
+    return 43;
+}
+
+//--- Use.cpp
+import Mod;
+int use() {
+    Base* base = new Base();
+    return 43;
+}
+
+// CHECK-NOT: @_ZTSW3Mod4Base = constant
+// CHECK-NOT: @_ZTIW3Mod4Base = constant
+// CHECK: @_ZTVW3Mod4Base = external unnamed_addr
+
+// CHECK-INLINE: @_ZTVW3Mod4Base = linkonce_odr unnamed_addr constant
+// CHECK-INLINE: @_ZTSW3Mod4Base = linkonce_odr constant
+// CHECK-INLINE: @_ZTIW3Mod4Base = linkonce_odr constant