The purpose of this paper is to explore how experienced teachers learn informally, and more specifically, how they learn through the activities they undertake when teaching classes. Regarding these activities we studied four aspects: behaviour, cognition, motivation and emotion. During one year, data were collected through observations of and interviews with four experienced teachers. For the analysis we used Eraut's distinction into three types of learning which differ in the degree of consciousness that is involved. We found several activities that represented each of these types of learning. The findings demonstrate how cognitive, affective, motivational and behavioural aspects are interrelated in classroom teaching and that learning from classroom teaching occurs at several levels of awareness. Hence, we argue that a theory of teacher learning should account for activities involved in the alignment of behaviour to plan and for the role of motivation and emotion. The findings suggest that fruitful development of the quality of teaching requires more attention for the relation between teachers' cognition, emotion, motivation and behaviour, and for promoting teachers' awareness of their implicit beliefs and behavioural tendencies.