Abstract: This prospective study examined whether Big Five traits and self-esteem predict voluntary and involuntary dropout from military training, beyond the effects of age, education, and self-reported physical fitness. We analyzed two independent samples, including 634 and 219 conscripts from the Swiss Armed Forces, using hierarchical logistic regression. Results indicate that lower self-esteem was associated with a higher likelihood of voluntary dropout, as hypothesized. Furthermore, lower levels of Big Five facet respectfulness were linked to an increased likelihood of voluntary dropout, and lower levels of facet creative imagination were linked to an increased likelihood of involuntary dropout. However, the effect of facets was less substantiated than that of self-esteem. None of the other variables significantly predicted dropout, and most hypothesized associations were not supported. We discuss potential explanations and highlight more promising predictors for future research. The findings contribute to our understanding of the predictive validity of personality scales and have practical implications for military personnel managers. We recommend using self-esteem as a screening measure to identify recruits prone to voluntary dropout. The present study was limited by a low number of dropout cases and potential selection effects that may have reduced predictive associations prior to analysis.