diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -1124,6 +1124,9 @@
     Builder.defineMacro("__GLIBCXX_BITSIZE_INT_N_0", "128");
   }
 
+  if (LangOpts.RelativeCXXABIVTables)
+    Builder.defineMacro("__RELATIVE_CXX_ABI_VTABLES");
+
   // Get other target #defines.
   TI.getTargetDefines(LangOpts, Builder);
 }
diff --git a/clang/test/Preprocessor/predefined-macros.c b/clang/test/Preprocessor/predefined-macros.c
--- a/clang/test/Preprocessor/predefined-macros.c
+++ b/clang/test/Preprocessor/predefined-macros.c
@@ -199,3 +199,7 @@
 // CHECK-HIP-DEV: #define __HIPCC__ 1
 // CHECK-HIP-DEV: #define __HIP_DEVICE_COMPILE__ 1
 // CHECK-HIP-DEV: #define __HIP__ 1
+
+// RUN: %clang_cc1 %s -E -dM -o - -fexperimental-relative-c++-abi-vtables \
+// RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-RELATIVE-VTABLES
+// CHECK-RELATIVE-VTABLES: #define __RELATIVE_CXX_ABI_VTABLES 1