Police employees have an essential role in sustaining safety and harmony within communities, and they need to stay well as individuals in order to achieve this. Yet, their stressful work environment does not always afford optimal interpersonal interactions. In collaboration with the Dutch police force, the present project explored the effects of a mindfulness-based stress reduction (MBSR) training on the fostering of constructive interpersonal responses as well as individual well-being among employees of the Dutch police. In total, 133 police employees participated in a non-randomized waitlist controlled MBSR intervention. Participants filled out four online questionnaires spread evenly over a period of six months on constructive interpersonal responses and individual well-being. Linear mixed-effects analyses showed increases on various indicators of constructive interpersonal responding and individual well-being from pre-to post-training. These results were largely maintained at two-month follow-up. Interestingly, the positive effects of mindfulness intervention did not generalize across all measures of constructive interpersonal responding. Moreover, more frequent home practice predicted training benefits. We discuss the theoretical and practical implications of these findings.