Guided by an ecological perspective, two competing models were tested to examine how sibling relationship quality directly predicted or interacted with academic support from siblings to predict Latino adolescents' academic motivation (N = 258). Gender differences were examined utilizing multiple group analysis in structural equation modeling. Findings indicated that academic support from siblings was a significant predictor of both boys' and girls' academic motivation. In addition, sibling relationship quality was directly related to girls' academic motivation. Findings underscore the importance of examining the role that siblings play in Latino adolescents' academic motivation. (Contains 3 tables and 3 figures.)