Phenomenography is best known as an empirical research approach for investigating variation in conceptions of different educational phenomena--including learning, teaching and particular disciplinary concepts such as price in economics and motion in physics. It is less well-known for its theoretical basis, in terms of its epistemological and ontological claims (Marton and Booth 1997), and the variation theory of learning that has developed out of phenomenographic research and theory (Marton and Tsui 2004). This paper discusses what "conception" and "conceptual development" mean from a phenomenographic perspective and how phenomenography and variation theory can be combined with empirical research on academics' conceptions of teaching to inform the design of a postgraduate course for academics, aimed at the development of academics' understanding of the nature of teaching and learning.