In Benin, the unmet need for family planning services is especially high for adolescent girls and youth aged 15-24 years. The Challenge Initiative (TCI) supported the health system to assess and improve the quality of adolescent and youth sexual reproductive health services and enhance contraceptive uptake in 65 service delivery points (SDPs) of the Zou department. Between June 2019 and March 2021, TCI supported the health districts in Zou to train an assessment team to complete 3 cycles of quality assessments (QAs) using a QA checklist adapted to the local context. Based on assessment scores, the SDPs were categorized into poor, moderate, or good to excellent quality. The SDP managers developed remedial action plans after each cycle and for each SDP and followed up with supportive supervision. The first QA cycle showed that 52% of assessed SDPs achieved a good to excellent classification; by the second QA cycle, this reached 74%. However, the quality of adolescent- and youth-friendly health services regressed during the third QA cycle (during COVID-19 pandemic disruptions), when only 40% of SDPs achieved the good to excellent category. Between the first and second QA cycles, contraceptive uptake for adolescents and youth improved in the SDPs that had good or excellent quality of services, compared to the ones that were of lower quality (established significance level of 5% with a P value of .031). Further assessments could deepen our understanding of the internal and external factors that can affect service quality. The findings reinforce the importance of investing in quality improvement strategies to maximize the use of sexual and reproductive health services among adolescents and youth. They also underscore the need for a contextual and nuanced approach to ensure enduring results.