Since the 2000s, states have experimented with reforms to improve success among underprepared students traditionally assigned to developmental education (DE). Florida's reform under Senate Bill 1720 has been among the most comprehensive and wide-reaching. Recent public high school graduates and military personnel became exempt from DE, but nearly onethird of students, including those without a Florida standard high school diploma, were still required to take a placement test and enroll in DE if they scored below college-ready. The legislation also required colleges to offer accelerated instructional strategies for students remaining in DE, and provide enhanced advising and support services. Focusing specifically on nonexempt students, we use statewide data to conduct a difference-in-regression discontinuity analysis to examine differences in first-year math coursetaking outcomes for students on the margins of college readiness before and after the reform. While students narrowly assigned to DE tend to have a lower likelihood of taking and passing college-level courses relative to their college-ready peers, these students experienced larger gains after the reform when DE courses were offered in accelerated formats accompanied by support services. The reform also improved outcomes for students scoring above college-ready, which suggests that nonexempt students benefited from enhanced advising and support services too. [This article was published in "Journal of Higher Education" (EJ1281792).]