and other social organizations, such as theatre and club sports groups. In total, about one-third of undergraduate students are active members of one or another of 16 national fraternities and 13 sororities. William & Mary is also home to several unusual fraternal or similar organizations, including the Nu Kappa Epsilon music sorority and its male counterpart, Phi Mu Alpha Sinfonia; the Alpha Phi Omega co-ed service fraternity; gender-inclusive Phi Sigma Pi and other honor fraternities.
=== Secret societies ===
Several student secret societies exist at the college, including the Flat Hat Club, Seven Society, 13 Club, Bishop James Madison Society, and Wren Society.
=== Queens' Guard ===
The Queens' Guard was established on February 8, 1961, as a special unit of the Army Reserve Officers' Training Corps and was affiliated with the Pershing Rifles. The Guard was described by former President Davis Young Paschall as "a unit organized, outfitted with special uniforms, and trained in appropriate drills and …
