Disciplinary knowledge lies at the heart of academic work. However, connecting academics' disciplinary knowledge to their professional development as teachers has been a longstanding challenge for (research-intensive) universities. This is reflected in criticism of the practices that aim to support the professional development of university teachers. In order to create better connections, a deeper understanding is needed of how academics' disciplinary knowledge relates to the development of their teaching. In this paper, we therefore aim to advance theoretical insights about how academics' disciplinary knowledge connects to their professional development as university teachers. We do so by providing a conceptual analysis of teacher expertise and teacher knowledge perspectives. Literature discussed as part of the teacher expertise perspective provides insights into how knowledge is structured in order to perform teacher tasks. In our discussion of the teacher knowledge perspective, we include bodies of literature about teachers' knowledge base to explore the role of disciplinary knowledge in how to teach and about powerful knowledge to explore the role of disciplinary knowledge in what to teach. Insights from these bodies of literature can, from a teacher knowledge perspective, offer theoretical underpinnings for connecting academics' disciplinary knowledge to their professional development as university teachers. Adaptive expertise and practical knowledge are identified as concepts that include elements of both teacher expertise and teacher knowledge perspectives. Based on the conceptual analysis, we identify and discuss three aspects related to supporting the professional development of university teachers where attention to connection with teachers' disciplinary knowledge is important.