diff --git a/app/src/queue.h b/app/src/queue.h
index 229ddb87..ed3d4c21 100644
--- a/app/src/queue.h
+++ b/app/src/queue.h
@@ -3,6 +3,7 @@
 #define QUEUE_H
 
 #include <stdbool.h>
+#include <stddef.h>
 #include <SDL2/SDL_assert.h>
 
 // To define a queue type of "struct foo":