Community-based programming to promote gender equity, often delivered through community-based girl groups (CBGGs, sometimes called “safe spaces”), is increasing. However, evidence is weak on how CBGGs are implemented and their effect on adolescent girls’ health and well-being. The authors conducted a comprehensive literature review to identify relevant CBGG programs. They explored how programs with CBGGs were designed and their effects. They also identified questions that merit further research to inform programming to empower girls and advance their well-being. By critically reviewing impact evaluation evidence on CBGGs in LMICs, the authors aimed to answer 4 questions: 1) What design features do CBGGs with impact evaluations have? 2) What did those evaluations measure? 3) What were the program effects on girls? 4) What type of study designs generated which results? Conclusions: CBGG program evaluations found positive effects on girl-level outcomes that are independent of external factors, like gender norm attitudes, and suboptimal performance on health behavior and health status, which rely on other people and systems. This delivery model has promise for building girls’ assets. Complementary actions to engage girls’ social environments and structures are needed to change behaviors and health status.