This chapter presents video-based interaction analysis and discusses its contributions to research on workplace learning and professional development. Interaction analysis is a multidisciplinary qualitative approach, borrowing principles from the micro-sociology of everyday life, ethnomethodology, conversational analysis and the ethnography of communication. It aims to provide a detailed description of how individuals coordinate their actions when experiencing social encounters and engaging in goal-directed actions collectively. Over the past two decades, the use of interaction analysis has expanded significantly into the field of workplace practices in institutional or professional contexts, particularly thanks to the influence of Workplace Studies or applied conversation analysis. More recently, video-based interaction analysis has also been applied to the field of initial and continuing vocational education. The theoretical principles on which interaction analysis is based have been transposed to training activities and are now considered significant contributors to workplace learning and professional development. An increasing number of experiments have attempted to train professionals using a video-based interactive analysis of their work. After presenting the theoretical principles and methodological procedures of video-based interaction analysis, this chapter illustrates how the approach might be implemented in the specific empirical context of early childhood educators reflecting on their interactional competencies when encountering parents as part of their work. Data collected during collective analysis sessions illustrate the sorts of learning experiences made possible by video-based interaction analysis when it is used in continuing education programmes for qualified workers.