The aim of the present study was to better understand the combined and unique effects of teacher-student and parent-child relationships in students' achievement motivation and self-esteem. Participants were 3450 high school students administered items assessing their interpersonal relationships, academic motivation and engagement, academic self-concept, and general self-esteem. Preliminary correlations showed that both teacher-student and parent-child relationships are significantly associated with achievement motivation and general self-esteem. Importantly, however, when using appropriate structural equation models to control for shared variance amongst predictors, findings showed that although teachers and parents are clearly influential, after controlling for gender, age, and the presence of both interpersonal relationships in the one model, teacher effects are stronger than parent effects, particularly in the academic domain.