This report describes the development and initial validation of the Response to Stressful Experiences Scale (RSES), a measure of individual differences in cognitive, emotional, and behavioral responses to stressful life events. We validated this instrument with active-duty and reserve components of military and veterans samples (N = 1,014). The resulting 22-item scale demonstrated sound internal consistency (alpha = 0.91-0.93) and good test-retest reliability (r = 0.87). Factor analysis suggested 5 protective factors: (a) meaning-making and restoration, (b) active coping, (c) cognitive flexibility, (d) spirituality, and (e) self-efficacy. Associations with other measures supported convergent, discriminant, and concurrent validity. In separate military samples, the RSES accounted for unique variance in posttraumatic stress disorder symptoms above and beyond existing scales measuring resilience-related constructs, thereby demonstrating incremental validity. The RSES provides a brief, reliable, and valid measure of individual differences in cognitive, emotional, and behavioral responses to life's most stressful events.