"Don't Ask, Don't Tell" (DADT) prohibited gays from serving openly in the military from December 1993 to September 2011. The present study, conducted over one year after DADT's repeal, utilized a survey of attitudes toward DADT that was previously administered to Marine Corps officers at the Naval Postgraduate School (NPS) in 1999, 2004, and 2010. This survey, re-administered to NPS Marine officers in November 2012, addressed the following areas: policy, cohesion, leadership, tolerance, unit effectiveness, and military readiness. A comparison of results from the four surveys shows a clear trend of increasing acceptance toward homosexuals in the military. Levels of acceptance tended to vary by Military Occupational Specialty and length of service. Additionally, many Marine officers continued to express concern about habitability and personal comfort. These and other issues were further explored with Marine officers in three focus-group sessions. Overall, study results indicated strong agreement that the current policy protects the rights of all Marines, regardless of sexual orientation. Finally, Marine officers expressed confidence that the training they received adequately prepared them to execute the repeal of DADT. The thesis includes appendices with survey trend data from 1999 to 2012 and response frequencies from a concurrent survey of Navy officers.