Despite recognition of the important role of health workers in providing adolescent-friendly sexual and reproductive health services (AFSRHS), evidence on strategies for improving performance is limited. This review sought to address: (1) which interventions are used to improve health worker performance in delivering AFSRHS? and (2) how effective are these interventions in improving AFSRHS health worker performance and client outcomes? Building on a 2015 review, a search for literature on 18 previously identified programs was conducted to identify updated literature and data relevant to this review. Data was systematically extracted and analyzed. Due to the parent review's eligibility criteria, all programs included health worker training. Otherwise, supervision was the most frequently reported intervention used (n=10). Components and methods related to quality of trainings and supervision varied considerably in program reports. Nearly half of programs described employing processes to ensure availability of basic medicines and supplies (n=7). Other interventions (policies, standards, and job descriptions [n=5]; refresher trainings [n=5]; job aids or other reference material [n=3]) were less commonly reported to have been employed. No discernible patterns emerged in the relationship between interventions and outcomes of interest. Multi-faceted complementary strategies are recommended to improve health worker performance to deliver AFSRHS; however, this was uncommonly reported in the programs that we reviewed. Effectiveness and cost-effectiveness evaluations of interventions and intervention packages are needed to guide efficient use of limited resources to enhance health worker capacity to deliver AFSRHS. In the interim, programs should be developed and implemented based on available existing evidence on improving health worker performance within and outside adolescent health. This review is the first to examine the interventions commonly used to improve health worker performance in delivering AFSRHS. The findings indicate a need for additional effectiveness and cost-effectiveness evaluations of such interventions. In the meantime, existing evidence on improving health worker performance within and outside adolescent health must be integrated more thoughtfully into program planning and implementation.