diff --git a/absl/base/internal/thread_annotations.h b/absl/base/internal/thread_annotations.h
index 4dab6a9c150..8c5c67e0df2 100644
--- a/absl/base/internal/thread_annotations.h
+++ b/absl/base/internal/thread_annotations.h
@@ -38,6 +38,13 @@
 #ifndef ABSL_BASE_INTERNAL_THREAD_ANNOTATIONS_H_
 #define ABSL_BASE_INTERNAL_THREAD_ANNOTATIONS_H_
 
+// ABSL_LEGACY_THREAD_ANNOTATIONS is a *temporary* compatibility macro that can
+// be defined on the compile command-line to restore the legacy spellings of the
+// thread annotations macros/functions. The macros in this file are available
+// under ABSL_ prefixed spellings in absl/base/thread_annotations.h. This macro
+// and the legacy spellings will be removed in the future.
+#ifdef ABSL_LEGACY_THREAD_ANNOTATIONS
+
 #if defined(__clang__)
 #define THREAD_ANNOTATION_ATTRIBUTE__(x)   __attribute__((x))
 #else
@@ -268,4 +275,6 @@ inline T& ts_unchecked_read(T& v) NO_THREAD_SAFETY_ANALYSIS {
 
 }  // namespace thread_safety_analysis
 
+#endif  // defined(ABSL_LEGACY_THREAD_ANNOTATIONS)
+
 #endif  // ABSL_BASE_INTERNAL_THREAD_ANNOTATIONS_H_