We examined what and how experienced (mentor coaches) and novice coaches (coach participants) noticed as they analyzed a vignette of a coaching interaction between a coach and a teacher. We modified the van Es (2011) Learning to Notice Framework for a coaching context to analyze What and How coaches notice. We collected data from ten mentor coaches, who were experienced coaches and ten coach participants who were more novice coaches. We compared pre and post noticing for coach participants based on a two-year professional development model and compared the noticing to the mentor coaches. Findings indicate coach participant noticing for What and How coaches notice collectively shifted toward a greater focus on the teacher, included more interpretation, and was more specific from the beginning of the professional development to the end. The mentor coach noticing, on average, was more teacher-focused, interpretative, and specific than those of the coach participants. [For the complete proceedings, see ED657822.]