Abstract Introduction In military service members, high risk-taking behavior (RTB; e.g., looking to start a fight, reckless driving) leads to injury, judicial reprimand, and removal from military service. Consequently, reducing RTB has become a priority of the United States (U.S.) Army, and identifying modifiable antecedents of RTB has become critical. In non-military populations, in-lab studies have shown sleep restriction/deprivation leads to risky decision-making. We assessed whether sleep duration/quality and RTB are related in U.S. Army soldiers in operationally-relevant settings. Methods Sleep and RTB questionnaire data were collected in 4 unique samples: U.S. Army soldiers from an Armored Brigade Combat Team, Reserve Officer Training Corps (ROTC) Cadets, Special Operations infantrymen, and elite mountain warfare instructors. We aggregated data to conduct a mega-analysis, which is a combined analysis of original raw data. We assessed whether RTB (assessed with an in-house measure of soldier-specific RTB) was correlated with nightly sleep hours (n=2175), Insomnia Severity Index (n=1076), and Pittsburgh Sleep Quality Index scores (n=503). Next, using a linear regression, we assessed whether sleep duration was a predictor of RTB while controlling for relevant demographic factors (age, gender, marital status, combat experience, years of education, rank, years of service; n=1198). Results Higher RTB was correlated with lower sleep duration (r=-.23,p<.001), more insomnia symptoms (r=.29,p<.001), and poorer sleep quality (r=.20,p<.001). In the full model, lower age (B=-.02,p=.03) and higher combat experience (B=.05,p=.006) predicted higher RTB. Sleep duration remained a significant (and the strongest) predictor of RTB (B=-.18,p<.001). Conclusion Military leaders should work to build in more sleep opportunities and remove environmental sleep disruptors during training and deployment operations. Leaders should also monitor soldier behavior after military operations that require sleep loss in order to reduce RTB, and, consequently, increase the readiness of the force. Support This work was supported by the Military Operational Medicine Research Program (MOMRP). The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the US Army or of the US Department of Defense. This abstract has been approved for public release with unlimited distribution.