diff --git a/requests/api.py b/requests/api.py
index a2cc84d7..5f07a19f 100644
--- a/requests/api.py
+++ b/requests/api.py
@@ -18,8 +18,10 @@ def request(method, url, **kwargs):
 
     :param method: method for the new :class:`Request` object.
     :param url: URL for the new :class:`Request` object.
-    :param params: (optional) Dictionary or bytes to be sent in the query string for the :class:`Request`.
-    :param data: (optional) Dictionary or list of tuples ``[(key, value)]`` (will be form-encoded), bytes, or file-like object to send in the body of the :class:`Request`.
+    :param params: (optional) Dictionary, list of tuples or bytes to send
+        in the body of the :class:`Request`.
+    :param data: (optional) Dictionary, list of tuples, bytes, or file-like
+        object to send in the body of the :class:`Request`.
     :param json: (optional) A JSON serializable Python object to send in the body of the :class:`Request`.
     :param headers: (optional) Dictionary of HTTP Headers to send with the :class:`Request`.
     :param cookies: (optional) Dict or CookieJar object to send with the :class:`Request`.
@@ -62,7 +64,8 @@ def get(url, params=None, **kwargs):
     r"""Sends a GET request.
 
     :param url: URL for the new :class:`Request` object.
-    :param params: (optional) Dictionary or bytes to be sent in the query string for the :class:`Request`.
+    :param params: (optional) Dictionary, list of tuples or bytes to send
+        in the body of the :class:`Request`.
     :param \*\*kwargs: Optional arguments that ``request`` takes.
     :return: :class:`Response <Response>` object
     :rtype: requests.Response
@@ -102,7 +105,8 @@ def post(url, data=None, json=None, **kwargs):
     r"""Sends a POST request.
 
     :param url: URL for the new :class:`Request` object.
-    :param data: (optional) Dictionary (will be form-encoded), bytes, or file-like object to send in the body of the :class:`Request`.
+    :param data: (optional) Dictionary, list of tuples, bytes, or file-like
+        object to send in the body of the :class:`Request`.
     :param json: (optional) json data to send in the body of the :class:`Request`.
     :param \*\*kwargs: Optional arguments that ``request`` takes.
     :return: :class:`Response <Response>` object
@@ -116,7 +120,8 @@ def put(url, data=None, **kwargs):
     r"""Sends a PUT request.
 
     :param url: URL for the new :class:`Request` object.
-    :param data: (optional) Dictionary (will be form-encoded), bytes, or file-like object to send in the body of the :class:`Request`.
+    :param data: (optional) Dictionary, list of tuples, bytes, or file-like
+        object to send in the body of the :class:`Request`.
     :param json: (optional) json data to send in the body of the :class:`Request`.
     :param \*\*kwargs: Optional arguments that ``request`` takes.
     :return: :class:`Response <Response>` object
@@ -130,7 +135,8 @@ def patch(url, data=None, **kwargs):
     r"""Sends a PATCH request.
 
     :param url: URL for the new :class:`Request` object.
-    :param data: (optional) Dictionary (will be form-encoded), bytes, or file-like object to send in the body of the :class:`Request`.
+    :param data: (optional) Dictionary, list of tuples, bytes, or file-like
+        object to send in the body of the :class:`Request`.
     :param json: (optional) json data to send in the body of the :class:`Request`.
     :param \*\*kwargs: Optional arguments that ``request`` takes.
     :return: :class:`Response <Response>` object
diff --git a/requests/models.py b/requests/models.py
index 3d0e1f42..086e03c1 100644
--- a/requests/models.py
+++ b/requests/models.py
@@ -204,9 +204,13 @@ class Request(RequestHooksMixin):
     :param url: URL to send.
     :param headers: dictionary of headers to send.
     :param files: dictionary of {filename: fileobject} files to multipart upload.
-    :param data: the body to attach to the request. If a dictionary is provided, form-encoding will take place.
+    :param data: the body to attach to the request. If a dictionary or
+        list of tuples ``[(key, value)]`` is provided, form-encoding will
+        take place.
     :param json: json for the body to attach to the request (if files or data is not specified).
-    :param params: dictionary of URL parameters to append to the URL.
+    :param params: URL parameters to append to the URL. If a dictionary or
+        list of tuples ``[(key, value)]`` is provided, form-encoding will
+        take place.
     :param auth: Auth handler or (user, pass) tuple.
     :param cookies: dictionary or CookieJar of cookies to attach to this request.
     :param hooks: dictionary of callback hooks, for internal usage.
diff --git a/requests/sessions.py b/requests/sessions.py
index f6f9c0b5..dd525e2a 100644
--- a/requests/sessions.py
+++ b/requests/sessions.py
@@ -453,8 +453,8 @@ class Session(SessionRedirectMixin):
         :param url: URL for the new :class:`Request` object.
         :param params: (optional) Dictionary or bytes to be sent in the query
             string for the :class:`Request`.
-        :param data: (optional) Dictionary, bytes, or file-like object to send
-            in the body of the :class:`Request`.
+        :param data: (optional) Dictionary, list of tuples, bytes, or file-like
+            object to send in the body of the :class:`Request`.
         :param json: (optional) json to send in the body of the
             :class:`Request`.
         :param headers: (optional) Dictionary of HTTP Headers to send with the
@@ -550,7 +550,8 @@ class Session(SessionRedirectMixin):
         r"""Sends a POST request. Returns :class:`Response` object.
 
         :param url: URL for the new :class:`Request` object.
-        :param data: (optional) Dictionary, bytes, or file-like object to send in the body of the :class:`Request`.
+        :param data: (optional) Dictionary, list of tuples, bytes, or file-like
+            object to send in the body of the :class:`Request`.
         :param json: (optional) json to send in the body of the :class:`Request`.
         :param \*\*kwargs: Optional arguments that ``request`` takes.
         :rtype: requests.Response
@@ -562,7 +563,8 @@ class Session(SessionRedirectMixin):
         r"""Sends a PUT request. Returns :class:`Response` object.
 
         :param url: URL for the new :class:`Request` object.
-        :param data: (optional) Dictionary, bytes, or file-like object to send in the body of the :class:`Request`.
+        :param data: (optional) Dictionary, list of tuples, bytes, or file-like
+            object to send in the body of the :class:`Request`.
         :param \*\*kwargs: Optional arguments that ``request`` takes.
         :rtype: requests.Response
         """
@@ -573,7 +575,8 @@ class Session(SessionRedirectMixin):
         r"""Sends a PATCH request. Returns :class:`Response` object.
 
         :param url: URL for the new :class:`Request` object.
-        :param data: (optional) Dictionary, bytes, or file-like object to send in the body of the :class:`Request`.
+        :param data: (optional) Dictionary, list of tuples, bytes, or file-like
+            object to send in the body of the :class:`Request`.
         :param \*\*kwargs: Optional arguments that ``request`` takes.
         :rtype: requests.Response
         """