The purpose of the current investigation was to examine relations among maternal regulatory support, maternal antagonism, and mother–son relationship quality in relation to boys’ self-regulation during early adolescence. As part of a larger longitudinal study on 263 low-income, ethnically diverse boys, multiple informants and methods were used to examine associations among parenting practices and mother–son relationship quality in relation to boys’ self-regulation at ages 10 and 11. Multivariate analyses indicated that high levels of regulatory supportive parenting and relationship quality and low levels of antagonistic parenting independently predicted high levels of boys’ self-regulation at age 10. Only antagonistic parenting and relationship quality explained variance in levels of boys’ self-regulation at age 11 after accounting for prior self-regulation. The findings suggest that parenting and the context of the parent–child relationship are linked to self-regulation during early adolescence; however, it appears that parental antagonism and relationship quality, not maternal regulatory supportive parenting, contribute to rank-order change in self-regulation abilities. Implications of these results for research and practice are discussed.