diff --git a/README.md b/README.md
index 0ef75498c24e2f8f81a6064a907cf92c76ca90cb..9f5903e1fdb7d4137000208a618ae4d8fe0a6db8 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,11 @@ by simply running:
 make
 ```
 
+For the above command to succeed, the host needs to provide `sphinx-build` and
+the following sphinx extensions:
+* sphinx-tabs (supports tabbed content in the document)
+* sphinxcontrib.plantuml (supports plantuml content)
+
 ## Contributing
 
 See the `CONTRIBUTING.md` file.