School systems must undertake change to facilitate student achievement. Teachers who serve as resources for teachers and administrators, the teacher specialists, are being used by some school systems to implement change despite a deficit of professional studies exploring their effectiveness for this purpose. This mixed methods case study utilized change theory research to explore how a group of teacher specialists, acting as change agents, identified and met the needs of change adopters, the teachers, during a standards-based science resource implementation. Interviews with the teacher specialists were used to collect qualitative data, and the Stages of Concern Questionnaire (SoCQ) yielded quantitative data from teacher and specialist participants. Interview data were coded and categorized by professional development type and compared with the quantitative concerns profile of each teacher team. Through gap analysis, concerns ranking, and additional findings from quantitative data, the teacher specialists involved in this study were found to be adept at identifying the concerns of their teacher teams and providing purposeful professional development opportunities. Findings of this study shed light on how school educators can use teacher specialists to better design and deliver need-based professional development to teachers for the improvement of student achievement. [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.]