Action (vs. state) orientation describes the ability to modulate affect and is at the core of goal-directed self-regulation. However, evidence on stability and change over time is scarce. In Study 1 (N = 368 couples), we investigated measurement invariance of action orientation (measured with the ACS-90) as well as rank-order stability and mean-level change over a period of four years. We report results from three samples with young adults (Study 2). Measurement invariance was obtained for an adjusted ACS-90 scale after removing 4 items. Rank-order stability was high. In both studies, one of two subscales – prospective action orientation – increased over time. Positive change was most consistent for middle-aged adults, implying that self-regulatory abilities improve during middle adulthood.