Rooted in different theories and focusing on different elements of the socio-ecological fabric, climate transitions and transformations are conceived to have various forms. Although these literatures recognize the significance of learning and boundary spanning, systematic reviews of the role of knowledge in climate transitions are lacking. We review how targets of transformation, functions, types, and intermediaries of knowledge are conceptualized in five types of literature. We highlight that knowledge has a role as: the motor of transition in Transition Management literature, a consultant supporting transition in Transformational Climate Adaptation literature, an emancipator of transition in Transform Political and Economic Systems literature, the beacon guiding transition in Social–Ecological Transformation literature, and an Ad Hoc Committee motivating transition in Grassroots Transitions literature.