diff --git a/security/sandbox/common/SandboxSettings.h b/security/sandbox/common/SandboxSettings.h
index 433b1a6becff..70b5e6a517a4 100644
--- a/security/sandbox/common/SandboxSettings.h
+++ b/security/sandbox/common/SandboxSettings.h
@@ -7,6 +7,10 @@
 #define mozilla_SandboxSettings_h
 #include <cinttypes>
 
+#ifdef __OpenBSD__
+#include "nsXULAppAPI.h"
+#endif
+
 namespace mozilla {
 
 // Return the current sandbox level. This is the