Prior research has demonstrated that teacher-student relationships characterized by high levels of closeness and low levels of conflict are associated with higher levels of academic achievement among children. At the same time: (a) some research suggests that the quality of teacher-student relationships in part reflects the quality of early caregiving, and (b) the observed quality of early care by primary caregivers robustly predicts subsequent academic achievement. Given the potential for associations between teacher-student relationship quality and academic achievement to thus be confounded by the quality of early parenting experiences, the present study examined to what extent children's experiences in early life with primary caregivers (i.e., ages 3 to 42 months) and relationships with teachers during grade school (i.e., Kindergarten to Grade 6) were uniquely associated with an objective assessment of academic achievement at age 16 years in a sample born into poverty (N = 267; 45% female; 65% White/non-Hispanic; 41% of mothers did not complete high school). Early maternal sensitivity, though a strong predictor of later academic achievement, was not reliably associated with either teacher-reports or interview-based assessments of teacher-student relationship quality in grade school. Nonetheless, early maternal sensitivity and teacher-student relationship quality were each uniquely associated with later academic achievement, above and beyond key demographic variables. Taken together, the present results highlight that the quality of children's relationships with adults at home and at school independently, but not interactively, predicted later academic achievement in a high-risk sample.