diff --git a/README.md b/README.md
index 4794ad8e77..258609cc59 100644
--- a/README.md
+++ b/README.md
@@ -11,6 +11,8 @@ This repository contains two reference implementations of the database—one in
 
 ## Setup
 
+Noms works on Mac OS X and Linux. It probably works on other Unixen, but that's not tested. Windows is not currently supported.
+
 1. Install [Go 1.6+](https://golang.org/dl/)
 2. Ensure your [$GOPATH](https://github.com/golang/go/wiki/GOPATH) is configured
 3. Type type type: