diff --git a/addons/website_slides/models/slide_slide_resource.py b/addons/website_slides/models/slide_slide_resource.py
index 13eed97618b..7cd7dbe97ab 100644
--- a/addons/website_slides/models/slide_slide_resource.py
+++ b/addons/website_slides/models/slide_slide_resource.py
@@ -1,8 +1,11 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+from werkzeug.urls import url_encode
+
 from odoo import api, fields, models, _
 from odoo.exceptions import ValidationError
+from odoo.tools.mimetypes import get_extension
 
 
 class SlideResource(models.Model):
@@ -48,3 +51,12 @@ class SlideResource(models.Model):
         for record in self:
             if record.resource_type != 'file' and record.data:
                 raise ValidationError(_("Resource %(resource_name)s is a link and should not contain a data file", resource_name=record.name))
+
+    def _get_download_url(self):
+        self.ensure_one()
+        extension_file_name = get_extension(self.file_name) if self.file_name else ''
+        file_name = self.name if self.name.endswith(extension_file_name) else self.name + extension_file_name
+        return f'/web/content/slide.slide.resource/{self.id}/data?' + url_encode({
+            'download': 'true',
+            'filename': file_name
+        })
diff --git a/addons/website_slides/tests/test_slide_resource.py b/addons/website_slides/tests/test_slide_resource.py
index a10298dd737..ff50501ff54 100644
--- a/addons/website_slides/tests/test_slide_resource.py
+++ b/addons/website_slides/tests/test_slide_resource.py
@@ -2,14 +2,16 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from psycopg2 import IntegrityError
+from werkzeug.urls import url_quote
 
 from odoo.addons.website_slides.tests import common
 from odoo.exceptions import ValidationError
+from odoo.tests import HttpCase
 from odoo.tests.common import users
 from odoo.tools import mute_logger
 
 
-class TestResources(common.SlidesCase):
+class TestResources(common.SlidesCase, HttpCase):
 
     @users('user_officer')
     @mute_logger('odoo')
@@ -53,3 +55,34 @@ class TestResources(common.SlidesCase):
                 'resource_type': 'url',
                 'slide_id': self.slide.id,
             })
+
+    @users('user_officer')
+    def test_download_file_name_extension(self):
+        """ Test the resource download file name extension. """
+        resource_name = 'Test Resource with special character éè!?&"'
+        resource = self.env["slide.slide.resource"].create({
+            'name': resource_name,
+            'file_name': 'test.png',
+            'resource_type': 'file',
+            # A file for which _odoo_guess_mimetype and python_magic can detect the mime type: a png file
+            'data': 'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAACXBIWXMAAC4jAA'
+                    'AuIwF4pT92AAAAD0lEQVQIHQEEAPv/AIdaewLIAV0IjhGPAAAAAElFTkSuQmCC',
+            'slide_id': self.slide.id,
+        })
+        self.authenticate(self.env.user.login, self.env.user.login)
+
+        for name, file_name, expected_download_name in (
+                # The extension is determined from the file name extension
+                (resource_name, 'test.xlsx', f'{resource_name}.xlsx'),
+                (f'{resource_name}.xlsx', 'test.xlsx', f'{resource_name}.xlsx'),
+                (f'{resource_name}.txt', 'test.xlsx', f'{resource_name}.txt.xlsx'),
+                # .unknown_long_ext is considered as invalid so no extension is appended to the name
+                (f'{resource_name}.txt', 'test.unknown_long_ext', f'{resource_name}.txt'),
+                # No valid extension, the extension is detected at download time from the file content
+                (resource_name, 'test.unknown_long_ext', f'{resource_name}.png'),
+                (resource_name, 'test', f'{resource_name}.png'),
+        ):
+            resource.write({'name': name, 'file_name': file_name})
+            with self.subTest(name=name, file_name=file_name, expected_download_name=expected_download_name):
+                self.assertIn(f"filename*=UTF-8''{url_quote(expected_download_name)}",
+                              self.url_open(resource._get_download_url()).headers['Content-Disposition'])
diff --git a/addons/website_slides/views/website_slides_templates_lesson.xml b/addons/website_slides/views/website_slides_templates_lesson.xml
index f6bf4f2893b..d337c0db439 100644
--- a/addons/website_slides/views/website_slides_templates_lesson.xml
+++ b/addons/website_slides/views/website_slides_templates_lesson.xml
@@ -182,7 +182,7 @@
                             </t>
                             <div class="o_wslides_js_course_join ps-4" t-if="aside_slide._has_additional_resources()">
                                 <li t-foreach="aside_slide.slide_resource_ids" t-as="resource" t-if="resource.resource_type == 'file'">
-                                    <a t-attf-href="/web/content/slide.slide.resource/#{resource.id}/data?download=true" class="text-decoration-none small">
+                                    <a t-att-href="resource._get_download_url()" class="text-decoration-none small">
                                         <i class="fa fa-download me-1"/><span t-field="resource.name"/>
                                     </a>
                                 </li>
@@ -439,7 +439,7 @@
                         </span>
                         <div class="text-muted me-auto border-start ps-3">
                             <t t-foreach="slide.slide_resource_ids" t-as="resource" t-if="resource.resource_type == 'file' and resource.data">
-                                <a t-attf-href="/web/content/slide.slide.resource/#{resource.id}/data?download=true" t-esc="resource.name"/><br />
+                                <a t-att-href="resource._get_download_url()" t-esc="resource.name"/><br />
                             </t>
                         </div>
                     </div>
diff --git a/addons/website_slides/views/website_slides_templates_lesson_fullscreen.xml b/addons/website_slides/views/website_slides_templates_lesson_fullscreen.xml
index 63341c1d1c9..d35745495bd 100644
--- a/addons/website_slides/views/website_slides_templates_lesson_fullscreen.xml
+++ b/addons/website_slides/views/website_slides_templates_lesson_fullscreen.xml
@@ -151,7 +151,7 @@
                                 <div class="o_wslides_js_course_join ps-0" t-if="slide._has_additional_resources('file')">
                                     <t t-set="resources" t-value="slide.slide_resource_ids.filtered(lambda res: res.resource_type == 'file')"/>
                                     <li t-foreach="resources" t-as="resource" class="mb-1">
-                                        <a class="o_wslides_fs_slide_link" t-attf-href="/web/content/slide.slide.resource/#{resource.id}/data?download=true">
+                                        <a class="o_wslides_fs_slide_link" t-att-href="resource._get_download_url()">
                                             <i class="fa fa-download me-2"/><span t-esc="resource.name"/>
                                         </a>
                                     </li>