diff --git a/README.md b/README.md
index db3b7efb9..d86a30ce7 100644
--- a/README.md
+++ b/README.md
@@ -3,4 +3,20 @@ spaCy
 
 Fast, state-of-the-art natural language processing pipeline. Commercial licenses available, or use under AGPL.
 
+Tested (and working) with:
+
+* CPython 2.7
+* CPython 3.4
+* OSX
+* Linux 
+
+Untested:
+
+* Windows
+
+Fails with:
+
+* PyPy 2.7
+* PyPy 3.4
+
 http://honnibal.github.io/spaCy