diff --git a/doc/misc/eglot.texi b/doc/misc/eglot.texi
index df24cf2a1dc..47649455cec 100644
--- a/doc/misc/eglot.texi
+++ b/doc/misc/eglot.texi
@@ -919,6 +919,13 @@ Set this variable to non-nil if you'd like progress notifications coming
 from the language server to be handled by Emacs's progress reporting
 facilities.  If the value is the symbol @code{messages} the message
 buffer is used, else the progress is reported in the mode line.
+
+@cindex request cancellation
+@item eglot-advertise-cancellation
+Setting this variable to true causes Eglot to send special cancellation
+notification for certain stale client request.  This may help some LSP
+servers avoid doing costly but ultimately useless work on behalf of the
+client, improving overall performance.
 @end vtable
 
 @node Other Variables
diff --git a/etc/EGLOT-NEWS b/etc/EGLOT-NEWS
index f4621994b67..9deac73d9fc 100644
--- a/etc/EGLOT-NEWS
+++ b/etc/EGLOT-NEWS
@@ -20,6 +20,12 @@ https://github.com/joaotavora/eglot/issues/1234.
 
 * Changes in upcoming Eglot
 
+** New 'eglot-advertise-cancellation' variable
+
+Tweaking this variable may help some LSP servers avoid doing costly but
+ultimately useless work on behalf of the client, improving overall
+performance.
+
 
 * Changes in Eglot 1.18 (20/1/2025)
 
diff --git a/lisp/jsonrpc.el b/lisp/jsonrpc.el
index 1d3a983d41e..2431d00dad3 100644
--- a/lisp/jsonrpc.el
+++ b/lisp/jsonrpc.el
@@ -399,10 +399,12 @@ error of type `jsonrpc-error'.
 
 DEFERRED and TIMEOUT as in `jsonrpc-async-request', which see.
 
-If CANCEL-ON-INPUT is non-nil and the user inputs something while
-the function is waiting, then it exits immediately, returning
-CANCEL-ON-INPUT-RETVAL.  Any future replies (normal or error) are
-ignored."
+If CANCEL-ON-INPUT is non-nil and the user inputs something while the
+function is waiting, then any future replies to the request by the
+remote endpoint (normal or error) are ignored and the function exits
+returning CANCEL-ON-INPUT-RETVAL.  If CANCEL-ON-INPUT is a function, it
+is invoked with one argument, an integer identifying the cancelled
+request as specified in the JSONRPC 2.0 spec."
   (let* ((tag (cl-gensym "jsonrpc-request-catch-tag")) id-and-timer
          canceled
          (throw-on-input nil)
@@ -435,6 +437,8 @@ ignored."
                        (unwind-protect
                            (let ((inhibit-quit t)) (while (sit-for 30)))
                          (setq canceled t))
+                       (when (functionp cancel-on-input)
+                         (funcall cancel-on-input (car id-and-timer)))
                        `(canceled ,cancel-on-input-retval))
                       (t (while t (accept-process-output nil 30)))))
             ;; In normal operation, continuations for error/success is
diff --git a/lisp/progmodes/eglot.el b/lisp/progmodes/eglot.el
index 92eb1f2715c..f2fcbc0a4c2 100644
--- a/lisp/progmodes/eglot.el
+++ b/lisp/progmodes/eglot.el
@@ -571,6 +571,14 @@ under cursor."
           (const :tag "Execute custom commands" :executeCommandProvider)
           (const :tag "Inlay hints" :inlayHintProvider)))
 
+(defcustom eglot-advertise-cancellation nil
+  "If non-nil, Eglot attemps to inform server of cancelled requests.
+This is done by sending an additional '$/cancelRequest' notification
+every time Eglot decides to forget a request.  The effect of this
+notification is implementation defined, and is only useful for some
+servers."
+  :type 'boolean)
+
 (defvar eglot-withhold-process-id nil
   "If non-nil, Eglot will not send the Emacs process id to the language server.
 This can be useful when using docker to run a language server.")
@@ -1748,7 +1756,12 @@ Unless IMMEDIATE, send pending changes before making request."
   (unless immediate (eglot--signal-textDocument/didChange))
   (jsonrpc-request server method params
                    :timeout timeout
-                   :cancel-on-input cancel-on-input
+                   :cancel-on-input
+                   (cond ((and cancel-on-input
+                               eglot-advertise-cancellation)
+                          (lambda (id)
+                            (jsonrpc-notify server '$/cancelRequest `(:id ,id))))
+                         (cancel-on-input))
                    :cancel-on-input-retval cancel-on-input-retval))