Despite being widely implemented, little information exists on the effect of Value Clarification and Attitude Transformation (VCAT) workshops on health care provider knowledge and attitudes and abortion provision. Between 2019 and 2021, we conducted a cluster-randomised controlled trial among 101 private abortion-providing healthcare facilities in Ethiopia. We surveyed 217 providers prior to a VCAT workshop and again at 2 weeks, 6 months, and one year following VCAT workshop participation to understand abortion knowledge and attitudes, examined service statistics to assess abortion client volumes, and conducted in-depth interviews with 30 providers. We found that a VCAT workshop for providers increased abortion service provision. In the year following the workshop, intervention facilities served 13% more abortion clients than expected based on the control group trend (95% CI: 6%-21%,