Purpose: Co-teaching is a prevalent and productive coaching activity that coaches can leverage when working with teachers to support teaching and learning. However, there is insufficient research detailing how coaches can and should implement this coaching activity with teachers. Hence, the purpose of this qualitative interview study is to better understand the challenges that make co-teaching coaching cycles difficult for coaches to enact with in-service teachers, as well as the supports that can enhance the co-teaching experience for all involved parties. Design/methodology/approach: Fourteen semi-structured interviews were completed with one instructional coach and three elementary teachers in one school district in the USA. A combination of emergent as well as literature-driven codes was used to code the data. Findings: Overall, the participants pointed to six barriers they encountered when engaging in episodes of co-teaching, which spanned the broad categories of management and logistics, pedagogical dilemmas, and teacher learning. Furthermore, participants identified seven supports, spanning the broad categories of coach preparation, contextual factors, and management and logistics, that enabled them to productively engage in co-teaching. Originality/value: Although coaches may frequently engage teachers in coaching cycles involving co-teaching, there is a lack of research-based guidance for coaches about how to engage teachers most productively in co-teaching episodes. The findings from this study, which shed light on the challenges and support of co-teaching from one coach and three teachers, will enable coaches to more effectively co-teach with teachers as a form of high-quality professional development.