This paper elaborates on a number of key criticisms of Mezirow's transformative learning theory as well as providing arguments that validate it. Our paper exemplifies how Mezirow's theory can help adult educators and prospective school teachers understand that social structures and belief systems can influence student learning, that learners make meaning of their experiences in various ways which influence the sort of value systems they develop and that disorienting dilemmas often challenge the validity of one's values and the assumptions that underpin them. It exemplifies how Mezirow's theory can be put into practice in Adult and Higher Education via three case studies undertaken by the authors in different places, at different times and with different sets of learners. These include mature aged women returning to study, PhDs at a Swedish Engineering University, and domestic and international students studying at an Australian regional university. The case studies make use of a values survey, interviews and subsequent focus groups. Data from the survey and interviews are analysed and used to argue that transformative learning (Mezirow, 1991) can be practiced, to good effect, in university staff development and teacher education courses.