The Mason Middle School opened in 1995 and is named in memory of Paul W. Mason, the third president of the Fort Worth Country Day Board of Trustees. The Mason Middle School combines the original Upper School Science building, which was remodeled, and a newly-constructed two level annex. The remodeled former US Science building houses the business offices, the fifth and sixth grade science rooms, the Brown-Lupton Commons, and the Health and Wellness Counselor. On the bottom level of the new annex are the fifth and sixth grade classrooms, and seventh and eighth grade classrooms are on the upper level. All Middle School classrooms are equipped with the latest technological equipment and students have access to a central computer lab.