Using data from the National Survey of Adolescents (2004), we examine the community-level factors associated with early age at first sex among adolescents 14-19 years old in four African countries. Regression models are fitted separately by sex for each country for an outcome measuring early age at first sex, with a focus on community-level factors as potential influences of age on sexual debut. The community-level factors associated with adolescents’ sexual debut vary widely by both country and gender. Community influences that emerge as risk or protective factors of early sexual debut include community levels of adolescent marriage, wealth, religious group affiliation, sex education, parental monitoring, reproductive health knowledge, media exposure, membership in adolescent social group, and use of alcohol. Results indicate the importance of context-specific understanding of adolescents’ sexual behaviour and suggest how elements of place should be harnessed in the development of effective HIV and sexual health interventions.