Objectives <p>Mental health professionals are at elevated risk for psychological distress and reduced well-being, yet the effects of intensive Zen retreats in this population remain understudied. This study tested whether a 5-day silent, residential Zen-style mindfulness retreat yielded greater improvement than a time- and content-matched Dharma-talk comparator in distress, well-being, self-compassion, and situational self-awareness among health professionals.</p> Method <p>We conducted a nonrandomized controlled study in health professionals (retreat <i>n</i> = 120; control <i>n</i> = 92). The retreat involved a 5-day silent residential meditation practice, whereas the comparator consisted of daily pre-recorded Dharma talks without meditation, silence, or residential immersion. Outcomes were assessed immediately before and after the 5-day period.</p> Results <p>Relative to the active comparator, the retreat group showed greater reductions in stress and depressive symptoms, and greater improvements in self-compassion, situational self-awareness, and emotional, social, and psychological well-being. The largest adjusted between-group effects in ANCOVA models were observed for emotional, social, and psychological well-being (<i>η</i>²<i>ₚ</i> = 0.48–0.53) and stress (<i>η</i>²<i>ₚ</i> = 0.35).</p> Conclusions <p>Participation in a 5-day silent residential Zen-style mindfulness retreat was associated with improvements in affective symptoms, self-compassion, situational self-awareness, and well-being relative to an active psychoeducational comparator. These findings support the potential value of intensive contemplative retreat training for clinicians practicing dialectical behavior therapy (DBT), while warranting cautious interpretation given the nonrandomized design.</p> Preregistration <p>This study is not preregistered.</p>