In the last decade, clinical research on mindfulness and its positive effects on depression and anxiety have gained increased interest. Emotion regulation mediates the effects of mindfulness on mental health in clinical samples and among meditators. The present study examined whether these associations also generalize to the general population. Multi-group structural equation models tested with a sample of 853 adults whether difficulties in emotion regulation mediated the associations between overall mindfulness in addition to the Observe facet with symptoms of depression and anxiety and whether associations were similar among men and women. Emotion regulation partially mediated the associations of overall mindfulness with symptoms of depression and anxiety; associations with Observe were fully mediated. The magnitude of associations was similar among men and women. Mindfulness exerts positive effects on mental health among the general population mostly via improving emotion regulation. The training of mindfulness and emotion regulation may thus benefit mental health not only in clinical populations but also in the general population. Venues for further research are discussed.