diff --git a/BUILDING.md b/BUILDING.md
index 79ed96e3b..3def48955 100644
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -251,7 +251,7 @@ You will also need to install a few build tools and dependencies, which can be
 installed from [Homebrew](https://brew.sh/):
 
 ```
-brew install cmake ccache ninja nasm wxwidgets
+brew install cmake ccache ninja nasm mono wxwidgets
 ```
 
 You must set the `WX_CONFIG` environment variable for CMake to find wxWidgets