Abstract: Objectives: Thousands of Veterans file claims for military sexual trauma (MST)-related posttraumatic stress disorder (PTSD) disability through the Department of Veterans Affairs' (VA) Veterans Benefits Administration (VBA) annually to receive covered healthcare benefits and monthly nontaxable compensation for MST-related conditions. Although 72% of MST claims in 2021 were granted, prior reporting found other claims had been erroneously denied due to issues around VA staff not ordering disability exams for claims and not gathering necessary evidence on behalf of claimants. The present study explores decision-making processes around evidence-gathering for MST-related disability claims through interviews with VA staff who develop, rate, and evaluate MST disability claims (n = 21). Methods: Interviews occurred from October 2021 to January 2024 and were analyzed using rapid qualitative methods and inductive coding, revealing themes of ambiguity, beliefs, and discretion. Participants described MST "markers" (e.g., behavioral events or patterns indicating effects of MST) as difficult to reliably identify and demonstrated disagreements about what constituted a marker. Within this ambiguity, factors that shaped participants' decision-making included beliefs about the MST and its impacts, the veracity of Veteran PTSD and/or MST claims, and the role of VA staff. Participants' judgments appeared to depend in part on their beliefs about sexual assault myths and the trustworthiness of Veterans: those who endorsed sexual assault myths or believed Veterans often lie were more likely to approach MST claims with skepticism. Conclusion: Future policy and programming around MST claims processing should focus on reducing ambiguity and impacts of beliefs on discretion and objectivity.