Fixed typo
diff --git a/docs/development/getting-started.rst b/docs/development/getting-started.rst
index ab92c37..f036534 100644
--- a/docs/development/getting-started.rst
+++ b/docs/development/getting-started.rst
@@ -2,7 +2,7 @@
===============
Working on ``cryptography`` requires the installation of a small number of
-development dependencies in addtion to the depedencies for `installation`_.
+development dependencies in addition to the depedencies for `installation`_.
These are listed in ``dev-requirements.txt`` and they can be installed in a
`virtualenv`_ using `pip`_. Once you've installed the dependencies, install
``cryptography`` in ``editable`` mode. For example: