diff --git a/lib/rubygems/package.rb b/lib/rubygems/package.rb
index 10d9b85bf385..7f843f4e0a25 100644
--- a/lib/rubygems/package.rb
+++ b/lib/rubygems/package.rb
@@ -471,7 +471,7 @@ def install_location(filename, destination_dir) # :nodoc:
     destination = File.expand_path(filename, destination_dir)
 
     raise Gem::Package::PathError.new(destination, destination_dir) unless
-      destination.start_with? destination_dir + '/'
+      normalize_path(destination).start_with? normalize_path(destination_dir + '/')
 
     begin
       real_destination = File.expand_path(File.realpath(destination))