Objective: This study explored how high school and postsecondary academic parameters may relate to the choice of science, technology, engineering, and mathematics (STEM) major for students beginning their postsecondary education at community colleges. Our study incorporated these two clusters of factors into a statistical model to examine STEM major choice in community colleges. In particular, our study was one of the first to examine the direction and magnitude of the relationship between earned college credits in science laboratories and advanced mathematics and STEM college major selection. Method: We analyzed national data from the Education Longitudinal Study (2002) for students who were in 10th grade in 2002, entered community college as their first postsecondary institution, and declared a college major by 2006. A comprehensive integrated model was analyzed through binary logistic regression with the outcome variable of choice of STEM major or not. Results: We found math self-efficacy in high school, postsecondary introductory science laboratory courses, and postsecondary advanced mathematics courses were each positively associated with the choice of STEM major among community college students. Gender continues to be influential, with women less likely to pursue STEM than men. Contributions: Our study highlights the opportunities the science laboratory holds for engaging beginning community college students interested in STEM fields. The linchpin role of mathematics and science for students aspiring to study STEM is underscored by the findings of this study.