BACKGROUND: Research has documented occupational health disparities, including higher rates of work-related injuries, among temporary workers compared with workers in standard employment arrangements. According to guidance from the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH), both staffing companies and host employers are responsible for protecting the occupational safety and health (OSH) of temporary workers. To date, there has been little qualitative research on temporary worker OSH in the United States and a lack of evidence-based OSH programs designed to meet the needs of temporary workers. The aim of this study was to better understand the barriers to and facilitators of temporary worker OSH from the perspective of US staffing companies. METHODS: In-depth interviews were conducted with a convenience sample of representatives from 15 US staffing companies. Interviews were audio recorded, transcribed verbatim, and analyzed through a three-step process. RESULTS: Commonly mentioned barriers to temporary worker OSH include differential treatment of temporary workers by host employers; lack of understanding among host employers and staffing companies of joint OSH responsibilities; and workers' fear of job loss or other negative repercussions if they report an injury or illness or voice OSH concerns. Commonly mentioned facilitators of temporary worker OSH include conducting client assessments and site visits and fostering strong communication and relationships with both host employers and temporary workers. CONCLUSIONS: These findings can help inform the tailoring of OSH programs to promote health equity in temporary workers.