diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
index dc87cb8e15d..4a2ca45e633 100644
--- a/lisp/progmodes/project.el
+++ b/lisp/progmodes/project.el
@@ -514,11 +514,14 @@ project-try-vc
                 (lambda (b) (assoc-default b backend-markers-alist))
                 vc-handled-backends)))
              (marker-re
-              (mapconcat
-               (lambda (m) (format "\\(%s\\)" (wildcard-to-regexp m)))
-               (append backend-markers
-                       (project--value-in-dir 'project-vc-extra-root-markers dir))
-               "\\|"))
+              (concat
+               "\\`"
+               (mapconcat
+                (lambda (m) (format "\\(%s\\)" (wildcard-to-regexp m)))
+                (append backend-markers
+                        (project--value-in-dir 'project-vc-extra-root-markers dir))
+                "\\|")
+               "\\'"))
              (locate-dominating-stop-dir-regexp
               (or vc-ignore-dir-regexp locate-dominating-stop-dir-regexp))
              last-matches