We conducted a systematic review of the empirical literature examining the effectiveness of psychological interventions for post-traumatic symptomatology in police, firefighters, and paramedic personnel. The review process was guided by the PRISMA statement (Moher et al. [2009]. Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Medicine, 6(7), e1000097. https://doi.org/10.1371/journal.pmed.1000097) and Institute of Medicine’s Standards for Systematic Reviews (IOM [2011]. Finding what works in health care: Standards for systematic reviews. nihlibrary.nih.gov/sites/default/files/Finding_What_Works_in_Health_Care_StandardsforSystematic_Reviews_IOM_2011.pdf). An inter-disciplinary, multi-national research team with expertise in mental health trauma and occupational stress in high risk professions was engaged at each stage of the review. Two team members rated each study in terms of quality and contribution to the research question. Twenty-one studies were identified: 9 case studies, 2 single-group studies, 8 randomised controlled trials, and 2 studies examining work leave. Most of the studies were limited by small sample sizes and absence of active control conditions. Research limitations reduce the ability to draw definitive best practices recommendations; however, the increase in randomised controlled trials provides encouraging signs that trauma-focused psychotherapies can be effective for first responders.