This study examines the value of SAT Math scores for predicting first-year college math course performance, beyond HSGPA, and across colleges and universities of varying selectivity. Findings demonstrate that SAT Math scores are a highly useful tool for course placement, above and beyond HS grades, and that the validity of scores hold across institutional selectivity segments and regardless of when the SAT was taken in high school. Using data from 152,829 students attending 54 higher education institutions, differential validity, placement accuracy, probability of success, and differential prediction analyses were conducted. Results indicated that all SAT Math score relationships with math course grades were positive, 0.50 or higher, demonstrating strong relationships. Moreover, the incremental validity of SAT scores beyond that of HSGPA alone was 0.10, a 20% increase. Additional analyses indicated that the admission selectivity did not differentially impact the relationship between SAT scores and math course grades. Findings from this study show that SAT Math scores are a highly predictive tool to ensure that students are prepared for first-year math coursework and to identify students who may need additional support to be successful.