diff --git a/porting/nimble/include/os/os.h b/porting/nimble/include/os/os.h
index 40fc267d3..f7a7ef9c5 100644
--- a/porting/nimble/include/os/os.h
+++ b/porting/nimble/include/os/os.h
@@ -47,7 +47,7 @@ extern "C" {
 typedef uint32_t os_sr_t;
 #define OS_ENTER_CRITICAL(_sr) (_sr = ble_npl_hw_enter_critical())
 #define OS_EXIT_CRITICAL(_sr) (ble_npl_hw_exit_critical(_sr))
-#define OS_ASSERT_CRITICAL() (assert(ble_npl_hw_is_in_critical()))
+#define OS_ASSERT_CRITICAL() assert(ble_npl_hw_is_in_critical())
 
 /* Mynewt components (not abstracted in NPL) */
 #include "os/endian.h"