diff --git a/addons/mail/static/src/components/thread_view/thread_view_tests.js b/addons/mail/static/src/components/thread_view/thread_view_tests.js
index 5230f252e03..69039d2e1b8 100644
--- a/addons/mail/static/src/components/thread_view/thread_view_tests.js
+++ b/addons/mail/static/src/components/thread_view/thread_view_tests.js
@@ -1138,6 +1138,49 @@ QUnit.test('delete all attachments of a message with tracking fields should stil
     );
 });
 
+QUnit.test('Post a message containing an email address followed by a mention on another line', async function (assert) {
+    assert.expect(1);
+
+    this.data['mail.channel'].records.push({ id: 11 });
+    this.data['res.partner'].records.push({
+        id: 25,
+        email: "testpartner@odoo.com",
+        name: "TestPartner",
+    });
+    await this.start();
+    const thread = this.env.models['mail.thread'].findFromIdentifyingData({
+        id: 11,
+        model: 'mail.channel'
+    });
+    const threadViewer = this.env.models['mail.thread_viewer'].create({
+        hasThreadView: true,
+        thread: [['link', thread]],
+    });
+    await this.createThreadViewComponent(threadViewer.threadView, { hasComposer: true });
+    document.querySelector('.o_ComposerTextInput_textarea').focus();
+    await afterNextRender(() => document.execCommand('insertText', false, "email@odoo.com\n"));
+    await afterNextRender(() => {
+        ["@", "T", "e"].forEach((char)=>{
+            document.execCommand('insertText', false, char);
+            document.querySelector(`.o_ComposerTextInput_textarea`)
+                .dispatchEvent(new window.KeyboardEvent('keydown'));
+            document.querySelector(`.o_ComposerTextInput_textarea`)
+                .dispatchEvent(new window.KeyboardEvent('keyup'));
+        })
+    });
+    await afterNextRender(() => {
+        document.querySelector('.o_ComposerSuggestion').click()
+    });
+    await afterNextRender(() => {
+        document.querySelector('.o_Composer_buttonSend').click();
+    });
+    assert.containsOnce(
+        document.querySelector(`.o_Message_content`),
+        `.o_mail_redirect[data-oe-id="25"][data-oe-model="res.partner"]:contains("@TestPartner")`,
+        "Conversation should have a message that has been posted, which contains partner mention"
+    );
+});
+
 });
 });
 });
diff --git a/addons/mail/static/src/models/composer/composer.js b/addons/mail/static/src/models/composer/composer.js
index 3bb12b29433..45e68546813 100644
--- a/addons/mail/static/src/models/composer/composer.js
+++ b/addons/mail/static/src/models/composer/composer.js
@@ -486,7 +486,7 @@ function factory(dependencies) {
          * @returns {mail.partner[]}
          */
         _computeMentionedPartners() {
-            const inputMentions = this.textInputContent.match(
+            const inputMentions = this.textInputContent.replace('\n', "\n ").match(
                 new RegExp("@[^ ]+(?= | |$)", 'g')
             ) || [];
             const unmentionedPartners = [];
@@ -556,7 +556,9 @@ function factory(dependencies) {
             if (this.mentionedPartners.length === 0 && this.mentionedChannels.length === 0) {
                 return body;
             }
-            const inputMentions = body.match(new RegExp("(@|#)" + '[^ ]+(?= | |$)', 'g'));
+            const inputMentions = body.replace("<br/>", "<br/> ")
+                .match(new RegExp("(@|#)" + '[^ ]+(?= |&nbsp;|$)', 'g'))
+                .filter(match => !match.endsWith("<br/>"));
             const substrings = [];
             let startIndex = 0;
             for (const match of inputMentions) {