For educational developers (also called academic or faculty developers) to facilitate change toward effective teaching and learning practices at any level, they must build trust and communicate credible expertise, often while conveying 'second-hand' educational knowledge to academics who then act on that knowledge in their own work. In this conceptual article, we propose a new credibility framework, drawing on the intertwined literature on trust and trustworthiness, non-positional leadership, cognitive authority, and educational development. Our framework delineates six interrelated dimensions that developers employ to build trust and promote evidence-informed change in their local contexts.