Objectives <p>This study examined whether dispositional mindfulness and participation in a mindfulness intervention were positively associated with the use of emotion regulation strategies.</p> Method <p>Mindfulness was assessed with a short form of the Comprehensive Inventory of Mindfulness Experiences. Emotion regulation was assessed with a newly developed vignette-based questionnaire focusing on cognitive reappraisal and situation modification. A total of 96 university students participated in a first assessment of dispositional mindfulness and emotion regulation. Subsequently, 24 students participated in a 4-week online mindfulness training based on an established MBSR program, while 29 served as wait-list control group and 43 as passive control group.</p> Results <p>Dispositional mindfulness was positively associated with both types of emotion regulation strategies in the entire sample. However, our mindfulness intervention only increased the use of cognitive reappraisal, but not situation modification. Additionally, intervention participants, but not those in the two control groups, showed an increase in mindfulness and a reduction in stress.</p> Conclusions <p>This study suggests that mindfulness is linked to both cognitive and behavioral regulation, but our mindfulness-based intervention mainly enhanced cognitive reappraisal. This suggests that mindfulness programs may overemphasize cognitive strategies and would benefit from more systematic integration of behavioral approaches.</p>