diff --git a/include/mimalloc-internal.h b/include/mimalloc-internal.h
index 2625187..df04c1b 100644
--- a/include/mimalloc-internal.h
+++ b/include/mimalloc-internal.h
@@ -10,7 +10,7 @@ terms of the MIT license. A copy of the license can be found in the file
 
 #include "mimalloc-types.h"
 
-#if defined(MI_MALLOC_OVERRIDE) && defined(__APPLE__)
+#if defined(MI_MALLOC_OVERRIDE) && (defined(__APPLE__) || defined(__OpenBSD__))
 #define MI_TLS_RECURSE_GUARD
 #endif