This study aimed to explore the relationship between high school transition preparation and student involvement and integration in college among first-year college students with disabilities. One hundred fifty-eight freshmen with disabilities were recruited from a southeastern university in U.S. The findings reveal that high school transition preparation was highly associated with student involvement and social and academic integration efforts in the postsecondary setting. The results highlight the need for transition support services to foster transition preparation to make a smooth transition from secondary education to postsecondary education for students with disabilities.