This study highlights the relationship between high school grade point average (GPA), ACT Composite score, and the likelihood of developmental course placement in college. Higher high school grade point averages (HSGPA) and ACT Composite scores were associated with lower probabilities of developmental course placement. This study also highlights how this relationship between college readiness measures and developmental course placement has evolved over time. The study sample consisted of 40,194 students from 10 different institutions who took the ACT test in a state that provides the ACT test to all 11th-grade students during the school day. Findings reveal that as HSGPA increases, the probability of developmental course placement decreases. These probabilities also change substantially across cohorts. This was not the case for ACT Composite score, however. As with HSGPA, an increase in ACT Composite score was associated with a decrease in the probability of developmental course placement. This study highlights the importance of colleges adopting a more holistic approach to developmental course placement. The use of multiple measures for developmental course placement not only aligns with best practices but can also help to facilitate a more equitable and effective education journey for students.