diff --git a/web_infrastructure/htpasswd b/web_infrastructure/htpasswd
index 62822c0a6ea..c0899224302 100644
--- a/web_infrastructure/htpasswd
+++ b/web_infrastructure/htpasswd
@@ -54,6 +54,10 @@ options:
       - Used with C(state=present). If specified, the file will be created
         if it does not already exist. If set to "no", will fail if the
         file does not exist
+notes:
+  - This module depends on the I(passlib) Python library, which needs to be installed on all target systems.
+  - On Debian, Ubuntu, or Fedora: install I(python-passlib).
+  - On RHEL or CentOS: Enable EPEL, then install I(python-passlib).
 requires: [ passlib>=1.6 ]
 author: Lorin Hochstein
 """