diff --git a/include/fmt/core.h b/include/fmt/core.h
index eadd4ab1..9e335957 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -251,7 +251,7 @@ FMT_API void assert_fail(const char* file, int line, const char* message);
 #    define FMT_ASSERT(condition, message) \
       ((condition)                         \
            ? void()                        \
-           : fmt::internal::assert_fail(__FILE__, __LINE__, (message)))
+           : ::fmt::internal::assert_fail(__FILE__, __LINE__, (message)))
 #  endif
 #endif