This paper explores two different ways of understanding communities of practice in relation to workplace learning. This is based upon a case study of secondary school teachers working and learning in four subject departments in two English schools. In spite of institutional similarities, the cultures and working practices of the departments were different, and influenced the learning of the workers significantly. In such contexts, a tight conceptualisation of community of practice can form a valuable intermediate scale of analysis, between the individual learner and wider organisational influences on learning. However, communities of practice can also have a valuable meaning in relation to the wider influences and in situations where close-knit groupings do not exist.