Historically Black colleges and universities (HBCUs) are important for diversifying the science technology, engineering, and mathematics (STEM) workforce. This study aims to develop a scale to understand the experiences of HBCU STEM students to spur research on the factors associated with HBCUs' success with recruiting, retaining, and graduating Black STEM students. Nearly 3,000 undergraduate STEM students across 30 HBCUs participated in this study. The authors conducted exploratory and confirmatory factor analysis to examine the construct validity. The survey had a seven-factor structure with a comparative fit index of 0.9 and high reliability with Cronbach's alpha ranging from 0.68-0.91. Five factors significantly predicted student outcomes, indicating predictive validity. The resulting survey, HBCU Student STEM Success Survey, provides a reliable and valid measure for HBCU STEM students' experiences.