The literature on professional development is replete with studies that utilize survey, interview, and classroom observation data, primarily collected post professional development experience, to explore teachers' knowledge, beliefs, and actions; however, we lack a clear understanding of teachers' learning process and reflections during the professional development. The current study aims to address the above mentioned gaps in the literature, by utilizing participant reflections and assignments during a summer professional development opportunity, to elucidate the process by which teachers learn about inquiry-based teaching and begin to implement it in their planning, in addition to factors they deem influential in this process. The findings address three questions about professional development: 1) participants' process of developing professionally, 2) features of effective professional development, and 3) the relationship between participants and the program. Furthermore, a web of interrelationships is revealed between participant-identified beneficial programmatic features and the participants' experiences, processes of personal, social, and professional development, evolving conceptions and beliefs, and the translation of these beliefs into practice, as evident in their immediate implementation of ideas in instructional planning.