What is the relationship between ACT scores and success in college? For decades, admissions policies in colleges and universities across the country have required applicants to submit scores from a college entrance exam, most typically the ACT (American College Testing) or SAT (Scholastic Aptitude Test). This requirement suggests that high school students' performance on these exams can help predict their academic success as college students. In fact, research conducted over the past four decades on the efficacy of the ACT assessment as a predictor of college success generally supports this belief; there is a strong positive relationship between performance on the ACT and college GPA (Noble, 1991; Noble, Davenport, Scheil, Pommerich, 1999; Noble & Sawyer, 2002; Paszczyk, 1994; Price & Kim, 1976; Stumpf & Stanley, 2002; Thornell & Jones, 1986). Although ACT scores can be highly successful in predicting future success in college, students' performance on the ACT is largely determined by the courses students take during high school (Paszczyk, 1994), and the high school they attended (Noble et al., 1999). The "quality of the education they receive" during high school, the rigor of their course work, and access, especially to rigorous math and science courses regardless of the grades they receive in those courses, largely determine their performance on the ACT--and their future success in college. A list of references and online resources is included.