Previous research on military interventions emphasizes that coups and coup-prevention reforms undermine the military’s warfighting performance and demographic diversity due primarily to ethnically, religiously, or ideologically motivated interventions on the military’s internal affairs, specifically its recruitment and promotion processes (Quinlivan 1999; Brooks 2003, 2006; Biddle and Long 2004; Pilster and Bohmelt 2011; Talmadge 2015; Narang and Talmadge 2017). However, my preliminary research on the Turkish case challenges existing explanations by, first, evincing a puzzling increase in merit-based promotions and drastic revisions in officer education programs in the immediate aftermath of military interventions between 1960 and 2007, each of which was accompanied by a comprehensive purge in the officer corps; second, revealing that post-coup purges fail to alter the ethnic and geographical composition of the officer corps. I argue that counterintuitive post-coup promotion patterns in the Turkish officer corps result from military leaders’ performance-sensitive self-coup proofing strategies that recognize the importance of officer corps’ quality for the military’s effectiveness, especially in the face of major security threats, an uncommon approach in civilian dictatorships where concerns over regime security often outweigh external threats. I base my findings on an individual-level analysis of the relationship between academic performance—the military academy and general staff college rankings—and the likelihood of career advancement—the highest rank and office achieved— in the Turkish officer corps. Through an event-history analysis, I trace each senior officer’s ethnic background and career path in the Turkish army, navy, air force and probe the influence of six military interventions between 1960 and 2007 on the promotion and retirement decisions about approximately 17,000 general staff officers and generals using the original HOCA (Historical Officer Career Advancement) Dataset I created. The HOCA data has been drawn from military academy registries, yearbooks, and Supreme Military Council decisions during three-year fieldwork in Turkey. I also conducted about 100 interviews with retired officers, scholars, journalists, and politicians of military background.