diff --git a/README.rst b/README.rst
index 74babaf7..a4279a4b 100644
--- a/README.rst
+++ b/README.rst
@@ -60,6 +60,9 @@ Meson Build system: [required]
 for the libcamera core: [required]
         python3-yaml
 
+for generating IPA interfaces: [required]
+        python3-ply
+
 for IPA module signing: [required]
         libgnutls28-dev openssl