diff --git a/README.md b/README.md
index e6acf3d7bfc..8a8afba3214 100644
--- a/README.md
+++ b/README.md
@@ -91,6 +91,8 @@ __NOTE:__ The bug tracker is _not_ for discussions. Please use our [official cha
 
 We are always looking for developers! Check [how to contribute](CONTRIBUTING.md) if you are willing to participate.
 
+__Legal notice__: If you have seen proprietary Microsoft Windows source code (including but not limited to the leaked Windows NT 3.5, NT 4, 2000 source code and the Windows Research Kernel), your contribution won't be accepted because of potential copyright violation.
+
 Try out cloud-based ReactOS development using Gitpod and Docker:
 
 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/reactos/reactos)