diff --git a/addons/test_website/controllers/main.py b/addons/test_website/controllers/main.py
index f36053cd38f..63333b8157e 100644
--- a/addons/test_website/controllers/main.py
+++ b/addons/test_website/controllers/main.py
@@ -44,6 +44,10 @@ class WebsiteTest(Home):
     def test_company_context(self):
         return request.make_response(json.dumps(request.context.get('allowed_company_ids')))
 
+    @http.route('/test_lang_url/<model("res.country"):country>', type='http', auth='public', website=True, sitemap=False)
+    def test_lang_url(self, **kwargs):
+        return request.render('test_website.test_view')
+
     # Test Session
 
     @http.route('/test_get_dbname', type='json', auth='public', website=True, sitemap=False)
diff --git a/addons/test_website/tests/test_is_multilang.py b/addons/test_website/tests/test_is_multilang.py
index 69259f32054..1c7d61801e1 100644
--- a/addons/test_website/tests/test_is_multilang.py
+++ b/addons/test_website/tests/test_is_multilang.py
@@ -24,3 +24,48 @@ class TestIsMultiLang(odoo.tests.HttpCase):
             self.assertEqual(fr_prefix + '/post', body.find('./form[@id="post"]').get('action'))
             self.assertEqual(fr_prefix + '/get_post', body.find('./a[@id="get_post"]').get('href'))
             self.assertEqual('/get_post_nomultilang', body.find('./a[@id="get_post_nomultilang"]').get('href'))
+
+    def test_02_url_lang_code_underscore(self):
+        website = self.env['website'].browse(1)
+        it = self.env.ref('base.lang_it').sudo()
+        en = self.env.ref('base.lang_en').sudo()
+        be = self.env.ref('base.lang_fr_BE').sudo()
+        country1 = self.env['res.country'].create({'name': "My Super Country"})
+
+        it.active = True
+        be.active = True
+        website.domain = 'http://127.0.0.1:8069'  # for _is_canonical_url
+        website.default_lang_id = en
+        website.language_ids = en + it + be
+        params = {
+            'src': country1.name,
+            'value': country1.name + ' Italia',
+            'type': 'model',
+            'name': 'res.country,name',
+            'res_id': country1.id,
+            'lang': it.code,
+            'state': 'translated',
+        }
+        self.env['ir.translation'].create(params)
+        params.update({
+            'value': country1.name + ' Belgium',
+            'lang': be.code,
+        })
+        self.env['ir.translation'].create(params)
+        r = self.url_open('/test_lang_url/%s' % country1.id)
+        self.assertEqual(r.status_code, 200)
+        self.assertTrue(r.url.endswith('/test_lang_url/my-super-country-%s' % country1.id))
+
+        r = self.url_open('/%s/test_lang_url/%s' % (it.url_code, country1.id))
+        self.assertEqual(r.status_code, 200)
+        self.assertTrue(r.url.endswith('/%s/test_lang_url/my-super-country-italia-%s' % (it.url_code, country1.id)))
+
+        body = lxml.html.fromstring(r.content)
+        # Note: this test is indirectly testing the `ref=canonical` tag is correctly set,
+        #       as it is required in order for `rel=alternate` tags to be inserted in the DOM
+        it_href = body.find('./head/link[@rel="alternate"][@hreflang="it"]').get('href')
+        fr_href = body.find('./head/link[@rel="alternate"][@hreflang="fr"]').get('href')
+        en_href = body.find('./head/link[@rel="alternate"][@hreflang="en"]').get('href')
+        self.assertTrue(it_href.endswith('/%s/test_lang_url/my-super-country-italia-%s' % (it.url_code, country1.id)))
+        self.assertTrue(fr_href.endswith('/%s/test_lang_url/my-super-country-belgium-%s' % (be.url_code, country1.id)))
+        self.assertTrue(en_href.endswith('/test_lang_url/my-super-country-%s' % country1.id))
diff --git a/addons/website/models/website.py b/addons/website/models/website.py
index 248c75fa77f..8533e9c7e9c 100644
--- a/addons/website/models/website.py
+++ b/addons/website/models/website.py
@@ -1105,7 +1105,7 @@ class Website(models.Model):
             for key, val in list(arguments.items()):
                 if isinstance(val, models.BaseModel):
                     if val.env.context.get('lang') != lang.code:
-                        arguments[key] = val.with_context(lang=lang.url_code)
+                        arguments[key] = val.with_context(lang=lang.code)
             path = router.build(request.endpoint, arguments)
         else:
             # The build method returns a quoted URL so convert in this case for consistency.