diff --git a/clang-tools-extra/clang-tidy/bugprone/BadSignalToKillThreadCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/BadSignalToKillThreadCheck.cpp
--- a/clang-tools-extra/clang-tidy/bugprone/BadSignalToKillThreadCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/BadSignalToKillThreadCheck.cpp
@@ -30,7 +30,8 @@
 
 void BadSignalToKillThreadCheck::check(const MatchFinder::MatchResult &Result) {
   const auto IsSigterm = [](const auto &KeyValue) -> bool {
-    return KeyValue.first->getName() == "SIGTERM";
+    return KeyValue.first->getName() == "SIGTERM" &&
+           KeyValue.first->hasMacroDefinition();
   };
   const auto TryExpandAsInteger =
       [](Preprocessor::macro_iterator It) -> Optional<unsigned> {
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone-bad-signal-to-kill-thread-undef-sigterm.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone-bad-signal-to-kill-thread-undef-sigterm.cpp
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone-bad-signal-to-kill-thread-undef-sigterm.cpp
@@ -0,0 +1,11 @@
+// RUN: clang-tidy %s --checks=-*,bugprone-bad-signal-to-kill-thread -- | count 0
+
+#define SIGTERM 15
+#undef SIGTERM // no-crash
+using pthread_t = int;
+int pthread_kill(pthread_t thread, int sig);
+
+int func() {
+  pthread_t thread;
+  return pthread_kill(thread, 0);
+}