diff --git a/docs/releases.rst b/docs/releases.rst
index 57525328..1b9e7e08 100644
--- a/docs/releases.rst
+++ b/docs/releases.rst
@@ -4,6 +4,7 @@ Release notes
 .. toctree::
    :maxdepth: 2
 
+   releases/v5.1.1
    releases/v5.1.0
    releases/v5.0.2
    releases/v5.0.1
diff --git a/docs/releases/v5.1.1.rst b/docs/releases/v5.1.1.rst
new file mode 100644
index 00000000..7fc4fb88
--- /dev/null
+++ b/docs/releases/v5.1.1.rst
@@ -0,0 +1,14 @@
+What's new in Tornado 5.1.1
+===========================
+
+Sep 16, 2018
+------------
+
+Bug fixes
+~~~~~~~~~
+
+- Fixed an case in which the `.Future` returned by
+  `.RequestHandler.finish` could fail to resolve.
+- The `.TwitterMixin.authenticate_redirect` method works again.
+- Improved error handling in the `tornado.auth` module, fixing hanging
+  requests when a network or other error occurs.