BACKGROUND: Men who have sex with men (MSM) in Kenya continue to face barriers to HIV testing, which leads to delays in HIV prevention and care. An HIV self-testing (HIVST) intervention was implemented in three Kenyan counties to increase coverage and frequency of HIV testing among MSM communities with high HIV prevalence. The evaluation study examined how HIVST can increase testing among MSM who are unaware of their status by increasing coverage, frequency, and early uptake of testing and support linkages to prevention and treatment. We share results from the process evaluation of the intervention implemented in partnership with MSM-led organizations. METHODS: For a 12-month period between August 2019 and July 2020, the project team conducted in-depth interviews with HIVST users, monthly meetings with programme implementation teams, and monthly monitoring data reviews. Polling booth surveys were also conducted with participants. The process evaluation explored the fidelity, feasibility, coverage, acceptability, quality, and effectiveness of the HIVST intervention. RESULTS: An average of 793 MSM received 1,041 HIVST kits on a monthly basis through different distribution channels. Of those who received HIVST kits, 67% were distributed to infrequent testers and non-testers. Testing frequency among users increased to 82% for those who had a recent test during the previous three months, compared to 58% of HIVST non-users. There was a high linkage to care and treatment services (84%) among those who tested reactive for HIV at endline. MSM shared preferring HIVST kits because of its convenience and privacy. During the COVID-19 pandemic, adaptations to the intervention were made to support ongoing HIV testing and linkages to services. CONCLUSION: The introduction of HIVST in MSM-led HIV prevention programmes was feasible with high acceptability. The involvement of the MSM community in the design, implementation and evaluation of the intervention was a key factor to intervention success.