diff --git a/base/include/android-base/threads.h b/base/include/android-base/threads.h
index f4ba809..dba1fc6 100644
--- a/base/include/android-base/threads.h
+++ b/base/include/android-base/threads.h
@@ -23,3 +23,8 @@
 uint64_t GetThreadId();
 }
 }  // namespace android
+
+#if defined(__GLIBC__)
+// bionic has this Linux-specifix call, but glibc doesn't.
+extern "C" int tgkill(int tgid, int tid, int sig);
+#endif
diff --git a/base/threads.cpp b/base/threads.cpp
index a71382b..48f6197 100644
--- a/base/threads.cpp
+++ b/base/threads.cpp
@@ -46,3 +46,9 @@
 
 }  // namespace base
 }  // namespace android
+
+#if defined(__GLIBC__)
+int tgkill(int tgid, int tid, int sig) {
+  return syscall(__NR_tgkill, tgid, tid, sig);
+}
+#endif