A growing literature has begun to document the effects of compassion training on a variety of important interpersonal behaviors (e.g., helping behavior). What is not yet well understood, however, is what impact compassion training has on affect and affect regulation. To examine this issue, we implemented a 9-week compassion training program in which 51 adults provided twice-daily ratings of four ... [Show full abstract] affective states (anxiety, calm, fatigue, alertness) as well as their desire and capability to regulate these affective states. In addition, participants provided weekly responses regarding five specific regulatory strategies. Analysis of day-to-day trajectories of affective experience showed a decrease in anxiety and increase in calmness. Day-to-day trajectories of affect regulation demonstrated that participants were more likely to choose to accept and thus not influence or modulate affective experience (as opposed to dampen, enhance, or hold on to or maintain the affective state). At the same time, participants also reported being more capable in meeting their respective regulatory goals. Finally, analysis of week-to-week trajectories of specific regulatory strategies over the course of the compassion training program demonstrated that participants shifted to lesser use of expressive suppression and greater acceptance when experiencing stress/anxiety. These results suggest that interventions such as compassion training may help modulate specific affective states and modify the use of and self-efficacy for specific regulatory strategies.