diff --git a/lib/pp.rb b/lib/pp.rb
index 04b1c43..253aecb 100644
--- a/lib/pp.rb
+++ b/lib/pp.rb
@@ -424,7 +424,7 @@ def pretty_print(q) # :nodoc:
 class File < IO # :nodoc:
   class Stat # :nodoc:
     def pretty_print(q) # :nodoc:
-      require 'etc.so'
+      require 'etc'
       q.object_group(self) {
         q.breakable
         q.text sprintf("dev=0x%x", self.dev); q.comma_breakable