This qualitative single case study used Michael Fullan's (2008) six secrets as a framework to explore the phenomenon of administrators' experiences developing, implementing and sustaining a team-teaching model with grades 3-8. Data was gathered from seven administrators who completed a questionnaire, interviews, and a focus group. This study was guided by three research questions: (1) What are administrators' experiences developing, implementing and sustaining a team-teaching model at a small suburban school district in northern Massachusetts? and (2) How do administrators describe factors they attribute to impacting the effectiveness of a team-teaching model? and (3) How do administrators share the responsibility of implementing a team-teaching model throughout the district? There were eight findings which were uncovered throughout this study. Those findings included, five major components necessary to implement and sustain team-teaching, administrator's ability to share in the communication and professional development of the program, the importance of the role of the special education facilitator, and the administrator's role and how it effects their rankings of the components. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]