diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index de203a2137f..053d44d5362 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -1647,7 +1647,7 @@ the process buffer."
   "Return non-nil if argument BUFFER is an ERC server buffer.
 If BUFFER is nil, use the current buffer.  For historical
 reasons, also return non-nil for channel buffers the client has
-parted or from which it's been kicked."
+parted or been kicked from."
   (with-current-buffer (or buffer (current-buffer))
     (and (eq major-mode 'erc-mode)
          (null (erc-default-target)))))
@@ -1669,8 +1669,13 @@ If BUFFER is nil, the current buffer is used."
 
 (defun erc-query-buffer-p (&optional buffer)
   "Return non-nil if BUFFER is an ERC query buffer.
-If BUFFER is nil, the current buffer is used."
-  (not (erc-channel-p (or buffer (current-buffer)))))
+If BUFFER is nil, use the current buffer."
+  (and-let* ((target (if buffer
+                         (progn (when (stringp buffer)
+                                  (setq buffer (get-buffer buffer)))
+                                (buffer-local-value 'erc--target buffer))
+                       erc--target)))
+    (not (erc--target-channel-p target))))
 
 (defun erc-ison-p (nick)
   "Return non-nil if NICK is online."
diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index 64229887ead..999d9f100c9 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -1227,6 +1227,35 @@
 
   (erc-tests-common-kill-buffers))
 
+(ert-deftest erc-query-buffer-p ()
+  ;; Nil in a non-ERC buffer.
+  (should-not (erc-query-buffer-p))
+  (should-not (erc-query-buffer-p (current-buffer)))
+  (should-not (erc-query-buffer-p (buffer-name)))
+
+  (erc-tests-common-make-server-buf)
+  ;; Nil in a server buffer.
+  (should-not (erc-query-buffer-p))
+  (should-not (erc-query-buffer-p (current-buffer)))
+  (should-not (erc-query-buffer-p (buffer-name)))
+
+  ;; Nil in a channel buffer.
+  (with-current-buffer (erc--open-target "#chan")
+    (should-not (erc-query-buffer-p))
+    (should-not (erc-query-buffer-p (current-buffer)))
+    (should-not (erc-query-buffer-p (buffer-name))))
+
+  ;; Non-nil in a query buffer.
+  (with-current-buffer (erc--open-target "alice")
+    (should (erc-query-buffer-p))
+    (should (erc-query-buffer-p (current-buffer)))
+    (should (erc-query-buffer-p (buffer-name))))
+
+  (should (erc-query-buffer-p (get-buffer "alice")))
+  (should (erc-query-buffer-p "alice"))
+
+  (erc-tests-common-kill-buffers))
+
 (ert-deftest erc--valid-local-channel-p ()
   (ert-info ("Local channels not supported")
     (let ((erc--isupport-params (make-hash-table)))