This study tested a proposed model consisting of mathematics anxiety, mathematics self-efficacy, and implicit theories of intelligence in predicting mathematics and science career interest in middle school students, while controlling for student math level. One hundred fifty-two seventh-grade students in a middle school in the USA participated in the study. Results revealed both similarities and differences on the relation among the intended variables by gender. The path analyses showed that, for boys, mathematics self-efficacy mediated the relation between implicit theories of intelligence and mathematics and science career interest. In addition, student mathematics level exerted a direct impact on mathematics anxiety, growth mindset, and career interest for boys. For girls, mathematics anxiety exerted a direct impact on their career interest. Implications of the results are discussed.