Objectives <p>This study examined the relationship between mindfulness and emotion regulation among college student-athletes, with attention to mindful acceptance and behavioral changes following Shaolin Zen meditation (SZM).</p> Method <p>Study 1 used a cross-sectional survey of 305 college student-athletes to examine associations between mindfulness dimensions and self-reported emotion regulation. Study 2 used a preliminary controlled pre-test/post-test design with 48 student-athletes assigned to an 8-week SZM program or an active control condition matched for duration and basic physical engagement. Participants completed a computerized emotion-evaluation task before and after the intervention, and behavioral data were analyzed using participant-level and trial-level models.</p> Results <p>In study 1, mindful acceptance accounted for additional variance in self-reported emotion regulation beyond mindful awareness. In study 2, the SZM group showed a larger pre- to post-intervention increase in valence ratings for high-arousal negative stimuli than the active control group. This pattern remained evident in participant-level robustness analyses, while reaction-time findings were not informative regarding mechanism.</p> Conclusions <p>Trait mindful acceptance was associated with self-reported emotion regulation among college student-athletes. SZM was associated with a shift toward less unpleasant ratings of high-arousal negative images, but this valence shift should not be interpreted as direct evidence of acceptance-based emotion regulation. The findings remain preliminary and may reflect affective dampening, desensitization, expectancy effects, acceptance-related processes, or other mechanisms not distinguished in this study.</p> <p>Preregistration</p> <p>This study is not preregistered.</p>