The influence of parental beliefs and behaviors on children's math confidence and performance is well documented, but few studies examine these associations over time, or in large samples of Latino/a families. This study used longitudinal data from 247 (114 sons and 133 daughters) mother-child dyads to examine whether maternal math gender stereotypes and math involvement predict changes in the mothers' behavior or changes in the child's perceived math competence. Maternal math gender stereotypes when children were in fifth grade predicted decreases in mothers' involvement in their daughter's math homework from fifth to sixth grade. Greater maternal math involvement in fifth grade predicted increases in sons' and daughters' perceptions of math ability from fifth to sixth grades.