This paper describes the professional development team (PDT) concept, reports results of a study of the development and year-long implementation of a PDT, and describes the effects of the PDT on school personnel and on subsequent implementation of a professional development school (PDS). The PDT is presented as a viable option for improving K-12 education, research, professional development, and teacher education through school-based interprofessional teams. The PDT that was studied was located in a middle school and consisted of four teachers, one university professor, five student teachers, and two methods field experience students. PDTs have many of the same goals and functions as PDSs; however, PDSs are generally schoolwide efforts rather than efforts that involve only one team of students, teachers, and college faculty. PDTs can serve as a stepping stone to PDS implementation, as well as a viable alternative if a more extensive PDS relationship between a school and a college is not possible. Data sources for the study included surveys of students and parents; participant observation; and interviews with team members, school administrators, and other education professionals. Results indicated that the teachers, students, preservice teachers, and college professor who were associated with the team perceived positive outcomes from the PDT's presence. Among the positive outcomes was the perception by school and college personnel that the PDT's existence laid the foundation for the school's becoming a PDS. Also discussed are some of the negative reactions to the PDT. (IAH)