diff --git a/README.rst b/README.rst
index e0f7a320..a9947f01 100644
--- a/README.rst
+++ b/README.rst
@@ -893,10 +893,10 @@ With Basic authentication:
 Environment variables
 ---------------------
 
-You can also configure proxies by environment variables ``HTTP_PROXY`` and
-``HTTPS_PROXY``, and the underlying Requests library will pick them up as well.
-If you want to disable proxies configured through the environment variables for
-certain hosts, you can specify them in ``NO_PROXY``.
+You can also configure proxies by environment variables ``ALL_PROXY``,
+``HTTP_PROXY`` and ``HTTPS_PROXY``, and the underlying Requests library will
+pick them up as well. If you want to disable proxies configured through
+the environment variables for certain hosts, you can specify them in ``NO_PROXY``.
 
 In your ``~/.bash_profile``:
 
@@ -910,7 +910,9 @@ In your ``~/.bash_profile``:
 SOCKS
 -----
 
-Homebrew-installed HTTPie comes with SOCKS proxy support out of the box. To enable SOCKS proxy support for non-Homebrew  installations, you'll need to install ``requests[socks]`` manually using ``pip``:
+Homebrew-installed HTTPie comes with SOCKS proxy support out of the box.
+To enable SOCKS proxy support for non-Homebrew  installations, you'll
+might need to install ``requests[socks]`` manually using ``pip``:
 
 
 .. code-block:: bash
diff --git a/httpie/cli.py b/httpie/cli.py
index 5ff0465a..43121e22 100644
--- a/httpie/cli.py
+++ b/httpie/cli.py
@@ -517,7 +517,8 @@ network.add_argument(
     help="""
     String mapping protocol to the URL of the proxy
     (e.g. http:http://foo.bar:3128). You can specify multiple proxies with
-    different protocols.
+    different protocols. The environment variables $ALL_PROXY, $HTTP_PROXY,
+    and $HTTPS_proxy are supported as well.
 
     """
 )