The Brigham Young University-Public School Partnership (BYU-PSP) has been serving K-12 public schools in Utah for 29 years. The Partnership includes five school districts, BYU's David O. McKay School of Education, and the seven arts and sciences colleges at BYU that participate in preparing teachers. This article describes the structure of the Partnership and explains how the nine essential elements of Professional Development Schools (PDS) are implemented within this partnership agreement. The BYU-PSP is unusual among PDS partnerships due to its size, scope, and longevity. All schools within the BYU-PSP districts are considered Partnership schools, but some participate more fully in the preparation of teachers, school psychologists, and administrators than others. One of the strengths of the Partnership is that it provides over 40 pre-service and in-service professional development programs. Insights and lessons learned are shared, with a particular focus on long-term sustainability of school-university partnerships. (Contains 1 figure.)