Early life stress is linked to childhood obesity. As children enter adolescence, early life stress may be associated with increased rejection sensitivity, resulting in activation of behavioral and physiological changes that contribute to higher body mass index (BMI). Understanding the potential influence of rejection sensitivity on the association between early life stress and BMI is important to examine in female adolescents. For this secondary data analysis, we hypothesized that female adolescents with greater early life stress and greater rejection sensitivity would exhibit higher BMI-for-age 12 months later. Seventy-eight adolescents (Mage = 13.1 years; 100% female sex; MBMI = 23.2 kg/m2) in the United States completed study procedures from 2012 to 2016. Among these procedures, the Psychosocial Schedule was used to assess cumulative early life stress and the Children's Rejection Sensitivity Questionnaire was used to assess anger and anxiety in response to rejection. Twelve months later, height and weight were measured to derive BMI-for-age. Higher early life stress was associated with higher BMI-for-age among female adolescents with low rejection-provoked anger (1 SD below the mean). However, this association was not observed among female adolescents with high rejection-provoked anger (1 SD above the mean). Finally, there was no significant interaction between early life stress and rejection-provoked anxiety in predicting BMI-for-age. Experiencing early life stress may interact with rejection-provoked anger, but not anxiety, to predict BMI-for-age. Findings inform a developmental perspective of how rejection sensitivity may influence the association between early life stress and early cardiometabolic risk.