diff --git a/src/dynapi/SDL_dynapi.c b/src/dynapi/SDL_dynapi.c
index 7574cf5f4..97bc21846 100644
--- a/src/dynapi/SDL_dynapi.c
+++ b/src/dynapi/SDL_dynapi.c
@@ -27,6 +27,7 @@
 #if defined(__OS2__)
 #define INCL_DOS
 #define INCL_DOSERRORS
+#include <os2.h>
 #include <dos.h>
 #endif