Whilst video has become a central reflective tool in teacher education and teacher professional development, video-based collaborative reflection in these contexts is just starting to gain traction as a research approach. Here we develop our understanding of this approach by examining how teacher noticing can be extended in teacher reflection. We focus on a research and development project that introduced a dialogic pedagogy in conjunction with the use of a microblogging tool in English secondary schools. Three teachers participated in meetings with researchers, presenting self-selected clips from their lessons for discussion. Analysis of the audio-recorded meetings revealed teachers’ preparedness to extend understanding by building on others’ experiences. This led to the teachers developing frames for action for future lessons informed by professional dialogue.