Contemplative teachings highlight the benefit of mindfulness practice to the practitioner and to those with whom they interact, yet very few studies on meditation to date have explored whether meditation training improves social interactions and relationships. Examining effects on emotion regulation in social contexts may be key to understanding meditation’s social consequences, for at least two reasons. First, prior research supports the benefits of mindfulness training for emotion regulation generally, and second, the dynamic nature of social contexts may place additional demands on attention and emotion regulation for which mindfulness appears well-suited. This study compared a brief mindfulness intervention with an active control group to assess whether and how mindfulness training may affect social emotion regulation, and thereby social interactions and relationships. In the lab, neural and behavioral responses to facial expressions were examined pre- and post-intervention. Outside the laboratory, participants completed smartphone-based surveys about their daily social interactions. The pattern of results across these measures indicated that mindfulness training may enhance people’s attention in social interactions in particular ways that benefit their emotional well-being during them. These findings offer exciting clues for further investigation regarding how benefits of mindfulness training may extend beyond the individual practitioner.