diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 4cddb2b0a..fcd866043 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -28,6 +28,12 @@ frustration later on.
 All submissions, including submissions by project members, require review. We
 use Github pull requests for this purpose.
 
+### Browser compatibility
+We care strongly about making Blockly work on all browsers.  As of 2017 we 
+support IE 10 and 11, Edge, Chrome, Safari, and Firefox.  We will not accept
+changes that only work on a subset of those browsers.  You can check [caniuse.com](https://caniuse.com/) 
+for compatibility information.
+
 ### The small print
 Contributions made by corporations are covered by a different agreement than
 the one above, the