diff --git a/test/lisp/button-tests.el b/test/lisp/button-tests.el
index e0944afa344..2f5ad795df2 100644
--- a/test/lisp/button-tests.el
+++ b/test/lisp/button-tests.el
@@ -59,6 +59,7 @@
   "Test `button--help-echo' with forms."
   (with-temp-buffer
     ;; Test text property buttons with dynamic scoping.
+    (setq lexical-binding nil)
     (let* ((help   (make-symbol "help"))
            (form   `(funcall (let ((,help "lexical form"))
                                (lambda () ,help))))
diff --git a/test/lisp/files-tests.el b/test/lisp/files-tests.el
index aa5150b4b73..b283a512a42 100644
--- a/test/lisp/files-tests.el
+++ b/test/lisp/files-tests.el
@@ -154,12 +154,14 @@ form.")
 (ert-deftest files-tests-permanent-local-variables ()
   (let ((enable-local-variables nil))
     (with-temp-buffer
+      (setq lexical-binding nil)
       (insert ";;; test-test.el --- tests  -*- lexical-binding: t; -*-\n\n")
       (hack-local-variables)
       (should (eq lexical-binding t))))
   (let ((enable-local-variables nil)
         (permanently-enabled-local-variables nil))
     (with-temp-buffer
+      (setq lexical-binding nil)
       (insert ";;; test-test.el --- tests  -*- lexical-binding: t; -*-\n\n")
       (hack-local-variables)
       (should (eq lexical-binding nil)))))