While the role of agency is widely acknowledged in socio-technical transition research, there remains a research gap on agency in transitions and a call for studies using an actor-centred approach to transition studies. In response to this call, this paper addresses the role of actors and, particularly, organisations in transitions. It examines the role of organisational change in socio-technical sustainability transitions and, more specifically, how transition initiatives may trigger and support these changes in organisations and systems. For this purpose, the paper draws on literature from both transition studies and organisational change management (OCM) to build a multi-scale, integrative theoretical heuristic. This addresses drivers and barriers for organisational change as an integral part of transition processes, connecting the micro level of the individual, the meso level of the organisation and the macro level of the broader system in which the organisation is located. With the goal of illustrating the links between OCM and transition studies, this paper empirically examines the impact of Region 2050, a large, multi-organisation transition initiative in Sweden, in terms of creating change within the organisations involved. The main focus is on how the organisations acquire the new knowledge and capabilities required for improving regional planning for sustainability. The empirical study identifies leverage points at the micro-, meso- and macro-levels, which may be used in order to change strategic planning processes. Three different theoretical concepts from transition studies and OCM that could help to foster long-term planning are also identified: (1) the macro-level of institutional plurality and its connection to the meso- (organisational) level; (2) collaboration as a key success factor on the organisational level; and (3) at the micro-level, the roles of individuals as change agents and boundary spanners. Overall, the case highlights the merits of the OCM literature for transition studies and their emphasis on understanding interacting processes operating at multiple scales.