Adolescent girls are more likely to experience early sexual debut than boys. However, the developmental context of their sexual behaviors is under-investigated. Using the socio-ecological model and Malawi Schooling and Adolescent Survey, we investigated factors crucial in determining the development of sexual behaviors of 416, 14-year-old girls in rural southern Malawi. We applied Bivariate Logistic Regression analysis to determine associations. Results showed that 353 (84.9%) experienced sexual intercourse, 60 (18.4%) had multiple sexual partners, and 32 (9.1%) used condoms or hormonal contraceptives. Participants' educational background, desire for higher education, reproductive health knowledge, and being monitored by teachers in school were positively associated with healthy sexual behaviors. Having a boyfriend, lack of schooling support, and being invited to teachers' homes were positively associated with risky sexual behaviors. Therefore, promoting adolescents' formal education, sexual health literacy, and safety in schools should be essential components of research and biobehavioral interventions targeting young adolescents in Malawi.