The “Testing an Occupational Stress Intervention for Harm Reduction Workers in Substance Misuse Settings” project targets the critical need for support among Harm Reduction Workers (HRWs), who are essential in the care continuum for Persons Who Use Drugs (PWUD). The initiative will develop and evaluate the Stress First Aid (SFA) program, facilitated by the South Southwest Addiction Technology Transfer Center (SSW ATTC), to alleviate high occupational stress and trauma that HRWs face. During the R61 planning phase, the project will adapt SFA specifically for HRWs and assess its feasibility through focus groups and pilot testing. The subsequent R33 phase will rigorously test the adapted SFA’s effectiveness in a cluster-randomized trial within the South Southwest ATTC region. The overarching goal is to bolster the HRWs’ mental health and job performance, ultimately improving the quality of care for PWUD, a group at high risk of overdose and related health complications.