Traditionally, teacher professional learning is often seen as something that mainly takes place in organized, formalized settings. This article takes a broader starting point: the idea that it can be understood as the result of the teachers' confrontations and interactions with and within their professional contexts, and that context can thus serve as a source for learning. To gain a closer understanding of the nature of these contexts, we start with exploring these contexts from a theoretical point of view. We then look for evidence for the role of different contexts in teacher learning autobiographies and learner reports, produced by a diverse group of experienced teachers (n = 18), as part of their course work in a master's programme. The findings suggest that three contexts can be identified -- a personal practice domain, a social domain, and a theoretical domain -- and that confrontations in each of these domains can take place planned as well as unplanned. The relevance of the study is that understanding the ways in which context can serve as a source for learning can contribute to the debate on how to stimulate teacher professional learning.