Teaching students to construct scientific understanding is complex. Teachers who develop noticing skills can attend and respond to students’ science ideas to move understanding forward. Traditional professional development (PD) approaches limit teachers’ opportunities to develop noticing skills. This study examined what aspects of a collaborative learning experience developed teachers’ ability to notice and investigated which features teachers perceived to effect change in their practice. This qualitative case involved 15 secondary science teachers in a week-long PD. They collectively led and observed Next Generation Science Standards instruction of 11 middle school students to promote analysis of practice in peer coaching sessions. All participants took turns teaching, observing, and coaching to note evidence of noticing. Instruments utilized were: participant field notes, reflections, video, and student work. Themes found to develop noticing ability were analysis of tools during peer coaching preparation, referencing of evidence during peer coaching sessions, and trust within the learning community. Features that participants indicated to effect change in their noticing ability were repeatedly practicing noticing skills through differing peer coaching roles, collaboratively teaching in front of peers to actively focus on practice, serving as coach and being coached to create collegial questions, choosing evidence to stimulate peers’ analysis, generating conceptions of students’ ideas, and reflecting on teachers’ responses. Recommendations include creating communities of practice where peers can share and develop noticing practice by analyzing evidence of students’ ideas and teachers’ responses from multiple perspectives.