diff --git a/lisp/textmodes/tex-mode.el b/lisp/textmodes/tex-mode.el
index d990a2dbfa9..b2a6416f379 100644
--- a/lisp/textmodes/tex-mode.el
+++ b/lisp/textmodes/tex-mode.el
@@ -705,17 +705,36 @@ tex-verbatim-environments
               "\\(?:_+\\(?:[^][[:space:][:cntrl:][:digit:]:\\\\{}()/#_=]+\\|"
               "#+[1-9]\\)\\)+\\)\\([:_]?\\)")
       (1 (ignore
-          (let* ((expr (buffer-substring-no-properties (match-beginning 1)
-                                                       (match-end 1)))
-                 (list (seq-positions expr ?_)))
-            (dolist (pos list)
-              (put-text-property (+ pos (match-beginning 1))
-                                 (1+ (+ pos (match-beginning 1)))
-                                 'syntax-table (string-to-syntax "_"))))))
+          (when tex-expl-region-list
+            (let ((match (match-beginning 1)))
+              (catch 'result
+	        (dolist (range tex-expl-region-list)
+	          (and (> match (car range))
+	               (< match (cdr range))
+                       (let* ((expr (buffer-substring-no-properties
+                                     (match-beginning 1)
+                                     (match-end 1)))
+                              (list (seq-positions expr ?_)))
+                         (dolist (pos list)
+                           (put-text-property (+ pos (match-beginning 1))
+                                              (1+ (+ pos (match-beginning 1)))
+                                              'syntax-table
+                                              (string-to-syntax "_"))))
+                       (throw 'result t))))))))
       (2 "_"))
      ("\\\\[[:alpha:]]+\\(:\\)[[:alpha:][:space:]\n]"
       (1 "_")))))
 
+(defvar-local tex-expl-region-list nil)
+
+(defun tex-expl-region-set (_beg _end)
+  (setq tex-expl-region-list nil)
+  (goto-char (point-min))
+  (while (re-search-forward "\\ExplSyntaxOn" nil t)
+    (let ((new-beg (point))
+          (new-end (re-search-forward "\\ExplSyntaxOff" nil t)))
+      (add-to-list 'tex-expl-region-list (cons new-beg new-end) t))))
+
 (defun tex-env-mark (cmd start end)
   (when (= cmd (line-beginning-position))
     (let ((arg (buffer-substring-no-properties (1+ start) (1- end))))
@@ -1308,6 +1327,8 @@ tex-common-initialization
                 #'tex--prettify-symbols-compose-p)
   (setq-local syntax-propertize-function
 	      (syntax-propertize-rules latex-syntax-propertize-rules))
+  (add-hook 'syntax-propertize-extend-region-functions
+                  #'tex-expl-region-set nil t)
   ;; TABs in verbatim environments don't do what you think.
   (setq-local indent-tabs-mode nil)
   ;; Set up xref backend in TeX buffers.