The purpose of this qualitative study was to explore professional development from the perspective of instructional leaders to identify if the assumptions of Knowles's (1990) Adult Learning Theory were present in the planning and implementation of continuing education. For the purposes of this research study, professional development was defined as opportunities for learning offered to teachers to support and enhance teacher practices. An instructional leader is defined as an educator, also known as a learning leader, focused on effective, research-based instruction and strategies. Instructional leaders plan and implement learning opportunities and demonstrate and share their knowledge to encourage student achievement, provide support of practitioners, improve student and educator practice, and promote continuous growth. A qualitative case study research design was utilized, and the research setting was dependent on the participants and the locations in which they were contracted to conduct continuing education sessions with teachers. The instructional leaders were committed to plan and present professional development at three different suburban schools surrounding a city in the Southeastern United States. The participants in the study were instructional leaders and educational consultants with at least 10 years of experience who work across school districts with multiple elementary, middle, and high school sites in suburban and urban districts. Data sources included two rounds of interviews, observations of planned and implemented professional development, and document analysis of staff development materials. The data were analyzed using thematic analysis that included within-case and cross-case investigation. [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.]