diff --git a/lib/facter/operatingsystem.rb b/lib/facter/operatingsystem.rb
index d757a9c..66fc0a4 100644
--- a/lib/facter/operatingsystem.rb
+++ b/lib/facter/operatingsystem.rb
@@ -1,3 +1,5 @@
+require 'facter/util/operatingsystem'
+
 Facter.add(:operatingsystem) do
   # Sabayon Linux is a variant of Gentoo so this resolution needs to come
   # before the Gentoo resolution.