As a global community, we need to understand better how a just transition can shift development paths to achieve net zero emissions and eliminate poverty. Our past development trajectories have led to high emissions, persistent inequality and a world that is fragmented across multiple contradictions. How can countries shift to development pathways that deliver zero poverty and zero carbon? In developing a theory of just transition, the article begins by reviewing a range of theoretical approaches from different traditions, building in particular on neo-Gramscian approaches. It applies and modifies core components of Gramsci’s approach, building a neo-Gramscian theory of just transitions around concepts of ideology, hegemony, change agents and fundamental conditions. The theory suggests how coalitions of change agents can come together behind a just transition. The coalition needs to gain broader support, establish a new cultural hegemony in support of just transitions and be able to transform the fundamental conditions of the 21st century. The article briefly considers how this better understanding can be applied to the practice of shifting development pathways. The penultimate section reflects on limitations, including that a fuller development of a theory of just transition will require application for detailed concrete examples and a community effort. Together, we might address the multiple challenges of our present conditions to transition to development that enables human flourishing and a healthy planet.