diff --git a/libc/bionic/raise.cpp b/libc/bionic/raise.cpp
index f69d90b..0dd0ad7 100644
--- a/libc/bionic/raise.cpp
+++ b/libc/bionic/raise.cpp
@@ -27,6 +27,7 @@
  */
 
 #include <pthread.h>
+#include <signal.h>
 
 int raise(int sig) {
   int rc = pthread_kill(pthread_self(), sig);