Climate budgets are increasingly being used in local climate governance, but it is not clear whether they have the potential to drive systemic change toward decarbonization. This study uses a political dynamics of decarbonization framework to assess the transformative potential of municipal climate budgets to catalyze changes across cultural, economic, political, and technological systems to overcome carbon lock-in. Document analysis and interviews with climate budget experts from Oslo, Fredrikstad, Hamar, Bergen, Arendal, B ae rum, Asker and the county of Agder in Norway were employed in this study to identify and discuss transformative conditions for decarbonization. Climate budgets are used to integrate climate change mitigation as a core element of municipal governance. This approach aims to integrate climate change mitigation into existing decision-making mechanisms and expand the mandates of municipal departments and agencies in executing and overseeing climate actions. Local climate budgets are also being used to catalyze changes across cultural, economic, political, and technological systems through the alignment of new laws, regulations, financial and institutional capacities, inter-municipal coalitions, and cooperation with the private sector. However, climate budgeting in cities and local governments faces multiple barriers. These include a lack of jurisdiction over emissions accounted for in climate budgets; inadequate legal frameworks to support municipal climate actions; and competition for financial and institutional resources with other public services expected by city residents. These findings deepen our understanding of the transformative change potential in local climate action experiments by emphasizing the role of political dynamics in overcoming carbon lock-in. Cities and local governments should reorient decision-making through carbon budgeting to prioritize climate change and broaden the roles of municipal departments and agencies. This approach can ensure that climate is integrated into municipal governance, from urban planning to public service delivery.Establishing monitoring and reporting mechanisms within the climate budgeting process enhances accountability and transparency by requiring municipal departments and agencies to regularly report their progress and the impact of their climate initiatives.Municipal programmes, urban planning, legislation, financial streams, and institutional capacity should be leveraged to drive systemic changes across cultural, economic, political, and technological systems towards city-wide decarbonization.