The aim of this research was to develop a grounded theory of educational leadership development, using generative dialogue (GD), as an approach to initiating and maintaining professional growth in school principals/vice principals in an urban school district in a relatively affluent region of Western Canada. In Wave I, GD interviews were conducted by a team of consultants, and anonymous data were voluntarily submitted to the research team (n = 37). In Wave II, confidential, one-on-one, audio-recorded virtual interviews were conducted with five participants. Data were transcribed and analysed using grounded theory. The grounded theory model integrated the findings from Wave I and Wave II. There were three final overarching themes: environment, relationships, and leadership. Professional growth was evident when a GD approach was used that emphasized both positive communication and self-reflection. Relationships were supported by a focus on safety and reflected honesty, which led to a positive school culture, while leadership was facilitated through supports and the supervisor role and led to improved accountability. In conclusion, GD serves a useful purpose for facilitating professional growth in educational leaders, but should be supplemented with other evidence-based approaches to meet school leaders' broader professional development needs, and goals of school improvement. Applicability and limitations of the study are discussed.