The purpose of this research was to understand in-service teachers' experiences with and ideas about mathematical creativity after participating in a targeted professional development program. The professional development program encouraged participants to think creatively and foster students' creativity. In this study I present the results from the main unit of analysis, 12 participants in a professional development program, along with a deep analysis of three exemplar teachers from each of the identified groups, "adherence to traditional teaching practices (traditional)," "appreciation for teaching for creativity (creative but hesitant)," and "teaching for creativity (creative)." The findings of this study highlight the combination of participants' personal characteristics, lesson plans, problem-solving processes, and the environment that allowed teachers to foster creativity among middle school mathematics students. It also describes challenges participants faced when addressing mathematical creativity and how professional development programs can further support teachers as they implement elements of mathematical creativity into their teaching practice. [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.]