diff --git a/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp b/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
--- a/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
+++ b/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
@@ -486,6 +486,9 @@
   NamingCheckFailure &Failure = NamingCheckFailures[ID];
   SourceRange Range(MacroNameTok.getLocation(), MacroNameTok.getEndLoc());
 
+  if (!isValidAsciiIdentifier(Info.Fixup))
+    Failure.FixStatus = ShouldFixStatus::FixInvalidIdentifier;
+
   Failure.Info = std::move(Info);
   addUsage(ID, Range);
 }
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone-reserved-identifier.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone-reserved-identifier.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone-reserved-identifier.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone-reserved-identifier.cpp
@@ -171,6 +171,11 @@
 // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: declaration uses identifier '_', which is reserved in the global namespace; cannot be fixed automatically [bugprone-reserved-identifier]
 // CHECK-FIXES: {{^}}int _;{{$}}
 
+// https://github.com/llvm/llvm-project/issues/52895
+#define _5_kmph_rpm 459
+// CHECK-MESSAGES: :[[@LINE-1]]:9: warning: declaration uses identifier '_5_kmph_rpm', which is reserved in the global namespace; cannot be fixed automatically [bugprone-reserved-identifier]
+// CHECK-FIXES: {{^}}#define _5_kmph_rpm 459{{$}}
+
 // these should pass
 #define MACRO(m) int m = 0