diff --git a/pw_sync/public/pw_sync/binary_semaphore.h b/pw_sync/public/pw_sync/binary_semaphore.h
index 43603ec10..ecb3e3122 100644
--- a/pw_sync/public/pw_sync/binary_semaphore.h
+++ b/pw_sync/public/pw_sync/binary_semaphore.h
@@ -13,6 +13,7 @@
 // the License.
 #pragma once
 
+#include <stdbool.h>
 #include <stddef.h>
 
 #include "pw_chrono/system_clock.h"
diff --git a/pw_sync/public/pw_sync/counting_semaphore.h b/pw_sync/public/pw_sync/counting_semaphore.h
index 8768bab36..cf2e90478 100644
--- a/pw_sync/public/pw_sync/counting_semaphore.h
+++ b/pw_sync/public/pw_sync/counting_semaphore.h
@@ -13,6 +13,7 @@
 // the License.
 #pragma once
 
+#include <stdbool.h>
 #include <stddef.h>
 
 #include "pw_chrono/system_clock.h"