INTRODUCTION: Assisted partner services (APS), or notification for sexual partners of people diagnosed with HIV, is an efficient, effective, and high yield strategy to identify people living with HIV and is recommended by the World Health Organization (WHO). However, there remains a need to further understand the acceptability of APS qualitatively from a client lens, particularly when APS is integrated into the national health system. We investigated acceptability of APS when integrated into HIV services in Kenya. METHODS: Starting in May 2018, APS was implemented in 31 health facilities in Kisumu and Homa Bay counties in western Kenya. From January to December 2019, we conducted in-depth interviews (IDIs) with female index clients (n = 16) and male sexual partners (n = 17) in 10 facilities participating in an APS scale up study. Interviews assessed APS satisfaction, perceived benefits of the intervention, and challenges that may affect delivery or uptake. We applied the Theoretical Framework of Acceptability by Sekhon et al. (2017) as a guide to organize our findings. RESULTS: We find that views of APS are often guided by an individual's trust in the intervention's design and implementation, and an interest to preserve one's health and that of one's family and children. There were strong and consistent acceptable views of APS as "doing good" and "saving a life" and as a means of showing love towards one's partner(s). The initial acceptability framing of individuals engaging with APS was predicated either on a feeling of comfort with the intervention, or a wariness of divulging sex partner personal information. Health care workers (HCWs) were seen to play an important role in mitigating participant fears linked with the intervention, particularly around the sensitive nature of HIV disclosure and sexual partners. Clients noted considerable challenges that affected acceptability, including the risk to the relationship of disclosing one's HIV status, and the risk of intimate partner violence. DISCUSSION: We found that APS is acceptable as a strategy to reach male sexual partners of females diagnosed with HIV, and these findings provide opportunities to inform recommendations for further scale-up. Opportunities such as focusing on intervention confidentiality and appropriate counseling, excluding female clients at risk of IPV from this intervention, and highlighting the altruistic benefits of APS to potential clients. Understanding the perspectives of clients receiving APS in a real-world setting may be valuable to policy-makers and stakeholders interested in scaling up or enhancing APS within health systems.