Despite increasing demand for workers in fields that are grounded in science, technology, engineering, and math (STEM), retention rates are low among relevant college majors. Using Web-based survey data from 290 STEM majors, the authors investigated links among personality, coping strategies, and STEM major commitment. Proactive personality was positively related to STEM major commitment and to the active planning coping strategy and negatively related to behavioral disengagement. Active planning was positively related to commitment to STEM majors and behavioral disengagement was negatively related to the outcome. Coping strategies fully mediated the relationship between proactive personality and commitment to STEM majors. (Contains 2 tables and 1 figure.)