The purpose of this study is to understand how and what leaders (a principal, district coach, regional coach, and district assistant superintendent) professionally noticed within a video club context as they watched mathematics lessons. Professional noticing refers to the extent to which leaders are able to move beyond forming general descriptions and able to interpret and elaborate on events, while making connections to broader principles of teaching and learning. In the study, school leaders and teachers engaged in multiple video club cycles in which they watched edited classroom videos of mathematics lessons and discussed the videos. Analysis focused on how and what was noticed. Results indicated that leaders' comments were categorized as noticing (either teacher or student aspects) in one-third of the stanzas in which they spoke. Stanzas coded for noticing usually occurred near the middle of the conversation. Findings indicate that leaders often made claims about students' thinking but did not verbalize evidence to support claims. Variations existed among the noticing of the leaders, with some leaders noticing at higher levels than others.