A shortage of female and minority students pursuing science, technology, engineering, and mathematics (STEM) careers has prompted researchers and policy makers to examine the current STEM supply pipeline. This study examined factors influencing STEM career aspirations of a nationally representative sample of 9th-grade students (N = 21,444). Characteristics of students who aspired to STEM careers and non-STEM careers were examined. Guided by the career aspirations model (Mau & Bikos, ), the authors conducted logistic regression analyses to investigate variables predicting STEM career aspirations. Results indicated that race, gender, socioeconomic status, math interest, and science self-efficacy were the most important predictors of STEM career aspirations. Counselors in school and related career services contexts are encouraged to consider these important factors in identifying high school students who are interested in STEM career choices, as well as in planning career interventions to facilitate their career paths. Future researchers could test the applicability of this model with middle school students or adults.