Mindfulness-based treatments have been identified as potentially effective for reducing posttraumatic stress symptoms; however, the validity of research has been questioned, especially among first responders, due to ill-defined aspects of mindfulness. This study investigated the relationship between various dimensions of mindfulness (utilizing the Kentucky Inventory of Mindfulness Skills; KIMS) and posttraumatic stress symptoms (utilizing the Impact of Event Scale-Revised; IES-R) among active-duty police officers (N = 183). Multiple regression analyses showed that greater IES-R avoidance and intrusion subscale scores were predicted by lower KIMS accepting without judgment subscale scores. Greater IES-R hyperarousal subscale scores were predicted by lower KIMS accepting without judgment and describing subscale scores. Implications of these findings are discussed.