Children from alternative households complete fewer years of schooling. Yet little is known about the implications of coresidence with grandparents for educational attainment. Using data from the National Longitudinal Study of Adolescent Health (N = 10,083), this study found that extended households with two biological parents were not detrimental to high school completion or college enrollment. Although coresidence with grandparents did not compensate for not living with two biological parents, it seemed to be beneficial for the educational attainment of youth from single-mother households. In contrast, skipped-generation households were associated with a persistent disadvantage for educational attainment. Limited socioeconomic resources partially accounted for the adverse effects of alternative households, whereas parenting quality did not explain these effects. Interactions of gender by household structure suggested that stepfather households could have negative consequences for high school completion and college enrollment only for girls.