This research was conducted to examine the influence of parental involvement, in the form of parent conversations, on mathematics achievement for high school girls. Data from the High School Longitudinal Study of 2009 (HSLS:09) public-use file provided a sample of 13,694 students, including 6,592 girls for our analyses. A scale for measuring parent conversations was developed and regression analyses were conducted to examine whether this scale variable predicted mathematics achievement. Results indicated that conversational parental involvement was a significant predictor of mathematics achievement for Black and White girls, but not Hispanic and Asian. Implications for research and policy initiatives are discussed.