diff --git a/sphinx/environment.py b/sphinx/environment.py
index 72f5d240e..9138c6f1b 100644
--- a/sphinx/environment.py
+++ b/sphinx/environment.py
@@ -1217,6 +1217,8 @@ class BuildEnvironment:
                 try:
                     refdoc = None
                     if url_re.match(ref):
+                        if title is None:
+                            title = ref
                         reference = nodes.reference('', '', internal=False,
                                                     refuri=ref, anchorname='',
                                                     *[nodes.Text(title)])
diff --git a/tests/test_build_html.py b/tests/test_build_html.py
index 3753d05be..2c5f291ef 100644
--- a/tests/test_build_html.py
+++ b/tests/test_build_html.py
@@ -459,3 +459,18 @@ def test_tocdepth_singlehtml(app):
 
         for xpath, check, be_found in paths:
             yield check_xpath, etree, fname, xpath, check, be_found
+
+
+@with_app(buildername='html', srcdir='(empty)')
+def test_url_in_toctree(app):
+    contents = (".. toctree::\n"
+                "\n"
+                "   http://sphinx-doc.org/\n"
+                "   Latest reference <http://sphinx-doc.org/latest/>\n")
+
+    (app.srcdir / 'contents.rst').write_text(contents, encoding='utf-8')
+    app.builder.build_all()
+
+    result = (app.outdir / 'contents.html').text(encoding='utf-8')
+    assert '<a class="reference external" href="http://sphinx-doc.org/">http://sphinx-doc.org/</a>' in result
+    assert '<a class="reference external" href="http://sphinx-doc.org/latest/">Latest reference</a>' in result