diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
index ac278edd40..b55c245368 100644
--- a/lisp/progmodes/project.el
+++ b/lisp/progmodes/project.el
@@ -352,15 +352,28 @@ project--remote-file-names
                 (concat remote-id file))
               local-files))))
 
+(defun project-includes-buffer-p (buffer dir)
+  "Return non-nil if the `default-directory' of BUFFER is below DIR."
+  (file-in-directory-p
+   (buffer-local-value 'default-directory buffer)
+   dir))
+
+(defcustom project-buffer-conditions
+  '(and (or buffer-file-name
+            (derived-mode . compilation-mode)
+            (derived-mode . dired-mode)
+            (derived-mode . diff-mode)
+            (derived-mode . comint-mode)
+            (derived-mode . eshell-mode)
+            (derived-mode . change-log-mode))
+        project-includes-buffer-p)
+  "A buffer predicate for matching what buffers belong to a project."
+  :type 'buffer-predicate)
+
 (cl-defgeneric project-buffers (project)
   "Return the list of all live buffers that belong to PROJECT."
-  (let ((root (expand-file-name (file-name-as-directory (project-root project))))
-        bufs)
-    (dolist (buf (buffer-list))
-      (when (string-prefix-p root (expand-file-name
-                                   (buffer-local-value 'default-directory buf)))
-        (push buf bufs)))
-    (nreverse bufs)))
+  (let ((root (expand-file-name (file-name-as-directory (project-root project)))))
+    (match-buffers project-buffer-conditions nil root)))
 
 (defgroup project-vc nil
   "Project implementation based on the VC package."
@@ -679,7 +692,7 @@ project-buffers
                      (project--git-submodules))))
          dd
          bufs)
-    (dolist (buf (buffer-list))
+    (dolist (buf (cl-call-next-method))
       (setq dd (expand-file-name (buffer-local-value 'default-directory buf)))
       (when (and (string-prefix-p root dd)
                  (not (cl-find-if (lambda (module) (string-prefix-p module dd))