diff --git a/os/macosx/macos.h b/os/macosx/macos.h
--- a/os/macosx/macos.h
+++ b/os/macosx/macos.h
@@ -2,5 +2,18 @@
 #define MACOS_H
 
 void ShowMacDialog ( const char *title, const char *message, const char *buttonLabel );
+void ShowMacAssertDialog ( const char *function, const char *file, const int line, const char *expression );
 
-#endif /* MACOS_H */
\ No newline at end of file
+// Since MacOS X users will never see an assert unless they started the game from a terminal
+// we're using a custom assert(e) macro.
+#undef assert
+
+#ifdef NDEBUG
+#define assert(e)       ((void)0)
+#else
+
+#define assert(e) \
+		(__builtin_expect(!(e), 0) ? ShowMacAssertDialog ( __func__, __FILE__, __LINE__, #e ): (void)0 )
+#endif
+
+#endif /* MACOS_H */