diff --git a/docs/DEVELOPMENT-OSX-NATIVE.md b/docs/DEVELOPMENT-OSX-NATIVE.md
index 479817dfb85..270a76e3385 100644
--- a/docs/DEVELOPMENT-OSX-NATIVE.md
+++ b/docs/DEVELOPMENT-OSX-NATIVE.md
@@ -167,6 +167,13 @@ Homebrew loves you.
 
     brew install phantomjs
 
+## ImageMagick
+
+ImageMagick is used for generating avatars (including for test fixtures).
+
+    brew install imagemagick
+
+
 ## Setting up your Discourse
 
 ###  Check out the repository