This action research study examines the development of distributed leadership practice among a new team of teacher leaders and their principal at an elementary school. Using a qualitative approach including a series of interviews, observations and journal entries, this study analyzes the interactions and changing roles of teacher leaders and their principal as they collaborate to provide school-wide professional development in English Language Development (ELD). The study draws on Spillane's model of distributed leadership practice (2006) as well as activity theory (Vygotsky, 1978; Leont'ev, 1989; Engestrom, 1999). Findings suggest that distributed leadership developed within a school climate of collaboration, where- teachers were able to choose meaningful leadership roles connected to teaching and learning. The school principal played a key role in supporting new leaders by communicating a common purpose, building on a school climate of collaboration, and modeling leadership tools and routines. [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.]