diff --git a/cerberus.h b/cerberus.h
index 7549af1..d677207 100644
--- a/cerberus.h
+++ b/cerberus.h
@@ -39,6 +39,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <unistd.h>
 #include <ctype.h>
 #include <err.h>
+#include <signal.h>
 #include <sys/types.h>
 #include <sys/wait.h>