This brief examines which students in the Houston Independent School District (HISD) are more likely to earn the STEM endorsement and whether STEM endorsement completion predicts college enrollment. Analyses show that gender, STEM magnet program enrollment, and cumulative high school grade point average (GPA) predict STEM endorsement completion. While STEM endorsement completion is associated with college choice, the relationship appears to be explained by academic performance measures, particularly SAT scores and GPA. In fact, if STEM and non-STEM students had the same test scores and grades, college enrollment gaps at 2-year-or-less; 4-year, less-selective; and 4-year, more-selective institutions would reduce. Overall, the findings suggest that the STEM endorsement functions, by design or coincidence, as a funneling mechanism for high-performing students into more-selective colleges and universities.