diff --git a/README.md b/README.md
index f7a93961a..cb7fbff07 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ Color and Black-and-White Noto emoji fonts, and tools for working with them.
 - This project uses Python 3. 
 - You need either [zopflipng](https://github.com/google/zopfli) or [optipng](ttp://optipng.sourceforge.net/). (Zopflipng is better (about 5-10%) but much slower.)
 - You need [pkg-config](https://www.freedesktop.org/wiki/Software/pkg-config/)
-
+- You need [pngquant](https://pngquant.org/)
 
 ## Building NotoColorEmoji
 This project uses a virtual environment to manage dependencies. Use the following steps to get up and running.