Objective: To identify a correlation between family support and maternal self-efficacy of adolescent mothers. Method: This cross-sectional study applied a consecutive sampling technique. The sample was 100 primiparous adolescent mothers. Instruments utilized were structured questionnaires, including a demographic questionnaire, Maternal Efficacy Questionnaire (MEQ), Postpartum Support System, Edinburgh Postnatal Depression Scale (EPDS), and Infant Characteristics Questionnaire (ICQ). The correlation of family support and maternal self-efficacy was analyzed using chi-square and logistic regression. Results: The results showed a significant correlation between family support and maternal self-efficacy of adolescent mothers. The family support that most influenced maternal self-efficacy of adolescent mothers was family instrument support, with Wald value of 34.720. Conclusions: Instrument support most affects maternal self-efficacy of adolescent mothers and encourages adolescents performing nurturing and mothering roles. © 2018 Elsevier España, S.L.U.