This study tested a social cognitive model of math/science career goals in a sample (N = 258) of Mexican American high school students. Familism and proximal family supports for math/science careers were examined as predictors of math/science: performance accomplishments, self-efficacy, interests, and goals. Results showed that the hypothesized model provided an adequate fit to the data. Familism predicted performance accomplishments and perceived family supports while perceived family supports predicted self-efficacy and goals. The final model explained 63% of the variance in interests and 53% of the variance in goals. Mediation tests showed that person-cognitive variables explained the relationships between contextual variables and goals. Contrary to hypotheses, interests did not predict goals and proximal family supports did not moderate the relationship between interests and goals. Results are discussed in terms of incorporating culture-specific values into interventions aimed at enhancing the math/science career interests and goals of Mexican American high school students.