OBJECTIVE: Efforts to prevent opioid overdose mortality have rapidly expanded, including community-based distribution of naloxone to laypeople. In turn, responding to the opioid overdose crisis has increasingly fallen on the shoulders of community laypeople. Yet, little attention has been given to studying the mental health consequences of responding to an opioid overdose for community laypeople. This study examined emotion dysregulation as a risk factor for posttraumatic stress disorder (PTSD) stemming from opioid overdose responding among community laypeople. METHODS: Participants were 80 community laypeople who had responded to an opioid overdose (M age = 39.10, 59.5% women, 86.3% white). RESULTS: Elevated emotion dysregulation was found in community laypeople with versus without PTSD stemming from opioid overdose responding. Limited access to effective emotion regulation strategies was uniquely associated with PTSD stemming from opioid overdose responding. CONCLUSIONS: Opioid overdose trainings may benefit from the addition of trauma first aid to bolster emotion regulation skills.