This article aims to describe informal learning as it might apply to the early professional development of inexperienced teachers in the first three years of their career, working in secondary schools in England and Wales. An attempt has been made to move the debate on from a narrowly conceived competencies agenda based on a formalised approach to learning, to conceptualising informal learning in the broadest possible terms in order to try and capture the complexities of learning from an individual teacher's cognitive, affective and behavioural perspective. This is encapsulated in a proposed model of informal learning that contains three key elements: implicit, reactive and deliberative. It is acknowledged that investigating implicit learning may well present researchers with difficulties but some research evidence is presented to support the importance of reactive and deliberative learning. (Contains 5 figures.)