Every year millions of high school students graduate unprepared for college-level work, resulting in persistent challenges with high remediation rates and low levels of degree attainment in postsecondary education. Policymakers have responded with a variety of reform efforts at the state and local levels including early assessments of college readiness, senior year transition courses in math and English for students at risk of placement into developmental education in college, summer bridge programs, and Early College High Schools. The purpose of this chapter is to explore the intended mechanisms of these reforms for academically unprepared students, the impacts on both short-term and long-term outcomes of postsecondary success, and common challenges to implementation. The empirical evidence on the effectiveness of these college readiness reforms is largely mixedwith the exception of Early College High Schools, which tend to demonstrate more consistently positive impacts on student success. The chapter concludes with considerations for future reform efforts and additional research to support academically underprepared students.