diff --git a/README.markdown b/README.markdown
index 5978b9cad..7405d5101 100644
--- a/README.markdown
+++ b/README.markdown
@@ -3,3 +3,9 @@ Sourcemeta Core
 
 Refer to the project website for documentation:
 [https://core.sourcemeta.com](https://core.sourcemeta.com).
+
+Contributing
+------------
+
+By contributing to this project, you agree to our organisation-wide
+[contribution guidelines](https://github.com/sourcemeta/.github/blob/main/CONTRIBUTING.md).