This guide introduces the model for the Diploma Plus high schools. The schools are small, alternative high schools run by districts, or charter schools, and some alternative programs supported by community colleges in partnership with school districts. The students served are primarily those who are over-age, under-credit, and at-risk for dropout. The guide provides a detailed explanation of how Diploma Plus high schools function, an explanation of their effectiveness, and easy-to-use charts and lists to understand the components of the school system and curriculum. Their model is built upon four guiding principles: a performance-based system, supportive school culture, effective supports, and a future focus. The performance system relies upon competency-based education. The students finish by completing internships, college courses, and/or community action projects, as a means to support the transition to postsecondary. The authors cite improved test scores, retention rates, and graduation rates as indicators of the program's effectiveness relative to traditional high schools serving similar high-poverty and minority populations.