Students' high school experiences often do not prepare them adequately for postsecondary education and the world of work. Special attention should be paid to increasing the rigor, relevance, and engagement of the high school curriculum, including for students who have traditionally faced barriers to successful postsecondary transitions. This Issue Brief reviews lessons from studies of selected policies and programs designed to improve students' preparation for postsecondary pathways. Special emphasis is placed on ways to help those who traditionally face substantial barriers to success, including low-income students, African American and Latino students, and students with disabilities. A list of additional resources is included. (Contains 1 table and 4 endnotes.)