diff --git a/lib/cmock_config.rb b/lib/cmock_config.rb
index f8c88f9..c1b495f 100644
--- a/lib/cmock_config.rb
+++ b/lib/cmock_config.rb
@@ -81,7 +81,7 @@ class CMockConfig
       require 'pathname'
       includes1 = options[:includes_c_post_header] || []
       includes2 = options[:unity_helper_path].map do |path|
-        Pathname(path).relative_path_from(Pathname(options[:mock_path])).to_s
+        Pathname(File.expand_path(path)).relative_path_from(Pathname(File.expand_path(options[:mock_path]))).to_s
       end
       options[:includes_c_post_header] = (includes1 + includes2).uniq
     end