diff --git a/include/ruby/assert.h b/include/ruby/assert.h
index 5b435da8b9..8967973bf8 100644
--- a/include/ruby/assert.h
+++ b/include/ruby/assert.h
@@ -101,7 +101,7 @@ RBIMPL_SYMBOL_EXPORT_END()
 # define RBIMPL_ASSERT_OR_ASSUME(_) RUBY_ASSERT(_)
 #elif defined(RBIMPL_HAVE___ASSUME)
 # define RBIMPL_ASSERT_OR_ASSUME(_) RBIMPL_ASSUME(_)
-#elif RBIMPL_HAS_BUILTIN(__builtin_assume) && RBIMPL_COMPILER_SINCE(Clang, 7, 0, 0)
+#elif !RUBY_ASSERT_NOASSUME && RBIMPL_HAS_BUILTIN(__builtin_assume) && RBIMPL_COMPILER_SINCE(Clang, 7, 0, 0)
 # define RBIMPL_ASSERT_OR_ASSUME(_) RBIMPL_ASSUME(_)
 #else
 # define RBIMPL_ASSERT_OR_ASSUME(_) /* void */