diff --git a/mail_quoted_reply/models/mail_compose_message.py b/mail_quoted_reply/models/mail_compose_message.py
index 6bb2fa291..af5022635 100644
--- a/mail_quoted_reply/models/mail_compose_message.py
+++ b/mail_quoted_reply/models/mail_compose_message.py
@@ -1,6 +1,6 @@
 from markupsafe import Markup
 
-from odoo import api, models
+from odoo import api, models, tools
 
 
 class MailComposeMessage(models.TransientModel):
@@ -13,3 +13,11 @@ class MailComposeMessage(models.TransientModel):
         if "is_quoted_reply" in context.keys() and context["is_quoted_reply"]:
             self.body += Markup(context["quote_body"])
         return
+
+    @api.model
+    def get_record_data(self, values):
+        result = super().get_record_data(values)
+        subj = self._context.get("default_subject", False)
+        if subj:
+            result["subject"] = tools.ustr(subj)
+        return result
diff --git a/mail_quoted_reply/models/mail_message.py b/mail_quoted_reply/models/mail_message.py
index 38cc520b4..f416b2a48 100644
--- a/mail_quoted_reply/models/mail_message.py
+++ b/mail_quoted_reply/models/mail_message.py
@@ -5,7 +5,6 @@ from odoo import models
 
 
 class MailMessage(models.Model):
-
     _inherit = "mail.message"
 
     def _prep_quoted_reply_body(self):
@@ -45,4 +44,10 @@ class MailMessage(models.Model):
             "force_email": True,
             "default_partner_ids": self.partner_ids.ids,
         }
+
+        # If the original message had a subject, we use it as a base for the
+        # new subject, adding a "Re:" at the beginning.
+        if self.subject:
+            action["context"]["default_subject"] = f"Re: {self.subject}"
+
         return action
diff --git a/mail_quoted_reply/static/src/models/message.esm.js b/mail_quoted_reply/static/src/models/message.esm.js
index 0065f0be2..918b00100 100644
--- a/mail_quoted_reply/static/src/models/message.esm.js
+++ b/mail_quoted_reply/static/src/models/message.esm.js
@@ -1,6 +1,6 @@
 /** @odoo-module **/
 
-import { registerPatch } from "@mail/model/model_core";
+import {registerPatch} from "@mail/model/model_core";
 
 import rpc from "web.rpc";
 
@@ -8,7 +8,6 @@ registerPatch({
     name: "Message",
 
     recordMethods: {
-
         messageReply() {
             var self = this,
                 msg_id = this.id;
@@ -17,7 +16,8 @@ registerPatch({
                 method: "reply_message",
                 args: [msg_id],
             }).then(function (result) {
-                return self.env.services.action.doAction(result,
+                return self.env.services.action.doAction(
+                    result,
 
                     {
                         onClose: async () => {
@@ -25,7 +25,6 @@ registerPatch({
                             self.env.bus.trigger("update-messages");
                         },
                     }
-
                 );
             });
         },
diff --git a/mail_quoted_reply/static/src/models/message_action.esm.js b/mail_quoted_reply/static/src/models/message_action.esm.js
index 8d56ff8ef..f56c10e03 100644
--- a/mail_quoted_reply/static/src/models/message_action.esm.js
+++ b/mail_quoted_reply/static/src/models/message_action.esm.js
@@ -1,7 +1,7 @@
 /** @odoo-module **/
 
-import { one } from "@mail/model/model_field";
-import { registerPatch } from "@mail/model/model_core";
+import {one} from "@mail/model/model_field";
+import {registerPatch} from "@mail/model/model_core";
 
 registerPatch({
     name: "MessageAction",
@@ -21,7 +21,9 @@ registerPatch({
         },
         sequence: {
             compute() {
-                return this.messageActionListOwner === this.replyMessageAction ? 1 : this._super();
+                return this.messageActionListOwner === this.replyMessageAction
+                    ? 1
+                    : this._super();
             },
         },
     },
diff --git a/mail_quoted_reply/static/src/models/message_action_list.esm.js b/mail_quoted_reply/static/src/models/message_action_list.esm.js
index 5ddaee32d..ff8d68d87 100644
--- a/mail_quoted_reply/static/src/models/message_action_list.esm.js
+++ b/mail_quoted_reply/static/src/models/message_action_list.esm.js
@@ -1,8 +1,8 @@
 /** @odoo-module **/
 
-import { clear } from "@mail/model/model_field_command";
-import { one } from "@mail/model/model_field";
-import { registerPatch } from "@mail/model/model_core";
+import {clear} from "@mail/model/model_field_command";
+import {one} from "@mail/model/model_field";
+import {registerPatch} from "@mail/model/model_core";
 
 export const MESSAGE_TYPES = ["email", "comment"];
 
diff --git a/mail_quoted_reply/static/src/models/message_action_view.esm.js b/mail_quoted_reply/static/src/models/message_action_view.esm.js
index 6441cdecc..5ce5b7b7c 100644
--- a/mail_quoted_reply/static/src/models/message_action_view.esm.js
+++ b/mail_quoted_reply/static/src/models/message_action_view.esm.js
@@ -1,12 +1,15 @@
 /** @odoo-module **/
 
-import { registerPatch } from "@mail/model/model_core";
+import {registerPatch} from "@mail/model/model_core";
 
 registerPatch({
     name: "MessageActionView",
     recordMethods: {
         onClick(ev) {
-            if (this.messageAction.messageActionListOwner === this.messageAction.replyMessageAction) {
+            if (
+                this.messageAction.messageActionListOwner ===
+                this.messageAction.replyMessageAction
+            ) {
                 this.messageAction.messageActionListOwner.message.messageReply();
             } else {
                 this._super(ev);
@@ -17,7 +20,10 @@ registerPatch({
         classNames: {
             compute() {
                 let classNames = this._super() || "";
-                if (this.messageAction.messageActionListOwner === this.messageAction.replyMessageAction) {
+                if (
+                    this.messageAction.messageActionListOwner ===
+                    this.messageAction.replyMessageAction
+                ) {
                     classNames += " fa fa-lg fa-reply";
                 }
                 return classNames;
@@ -25,7 +31,10 @@ registerPatch({
         },
         title: {
             compute() {
-                if (this.messageAction.messageActionListOwner === this.messageAction.replyMessageAction) {
+                if (
+                    this.messageAction.messageActionListOwner ===
+                    this.messageAction.replyMessageAction
+                ) {
                     return this.env._t("Reply");
                 }
                 return this._super();