Transformative learning (TL) has been one of the most important education theories since Jack Mezirow (1923–2014) formalized it as a social constructionist view of adult development in the late 1970s. Drawing on critical reflection and rational communication, Mezirow posited that a disorienting dilemma prompts questioning received worldviews and a search for alternative perspectives and roles. Over the past 30 years, transformative learning theory and practice have diversified in response to criticism of Mezirow’s model and a shifting emphasis on Jungian psychology and Freirian pedagogy, with a commensurate revaluation of the role of emotions, intuition, and creativity. While TL remains riddled with ambiguities and empirical challenges, it has positively influenced education for sustainable development. As a consequence, TL has become associated with a critical assessment of the historical context and dynamics at the heart of unsustainability as well as the institutional shortcomings of the modern educational establishment.