This paper describes a program at the Vallejo (California) School District involving the use of instructional support teams composed of principals and teachers from each school to promote instructional improvement by increasing school-site leadership and teamwork between administrators and teachers. First, background information is given to provide a contextual description of the school district setting, the recent history of staff development programs in the district, and the entire district staff development program. Second, a philosophical and conceptual description of the purpose of the teams is provided. Third, the selection, training, and function of the teams is outlined. Finally, a case study is provided of the operation of an instructional support team in one elementary school from the perspectives of a principal and a teacher who are team members. Advantages of the instructional support teams include (1) shared responsibility between administrators and teachers, (2) greater interaction among professionals over matters of importance, and (3) an ongoing means for developing and using staff expertise and leadership capacity. (TE)