Research suggests that earning college credits in high school increases the likelihood of postsecondary progress and graduation. In this study, we measure the impact of dual enrollment in high school and college courses through the College Now (CN) program on college enrollment for students in New York City. We use a regression discontinuity design (RDD) that estimates the causal local average effect of the treatment — eligibility for dual enrollment in college classes while in high school — on college enrollment. We find that being eligible for CN leads to a 7% point increase in the likelihood of college enrollment and an 8.6% point increase in the likelihood of enrollment in a four-year college. Students who were eligible for CN and enrolled in CN were 20% points more likely to enroll in college.