<p>The active participation of citizens in planning is a key requirement for achieving the Sustainable Development Goals. Previous studies have emphasised that urban digital twins (UDTs) have the potential to improve the participation and influence of citizens in the initial stages of planning. Despite this claim, no study has comprehensively analysed and tested this assertion. This study, however, tests and demonstrates how citizens could employ UDTs to seek agenda status for their claims and proposals in a policy system. The study applies an adapted multiple streams framework (MSF) to examine how citizens, as policy entrepreneurs, employed UDTs to influence the adoption of climate neutrality in Munich. The study uses a case study approach, utilising in-depth semi-structured expert interviews and document analysis to examine climate-neutral agenda-setting in Munich. The results demonstrate that policy entrepreneurs were able to influence climate neutrality by leveraging UDTs for air quality simulation, transportation modelling, waste management, vegetation analysis, and energy demand estimation. Additionally, the opportunity to simulate interventions before implementation makes UDTs relevant tools for assessing climate-neutral action plans, thereby making them pivotal tools for achieving climate neutrality. Addressing the limitations of previous studies, this research supports and provides empirical evidence, emphasising that urban digital twins can help citizens influence urban decisions and policy actions, thereby increasing their decision-making space, role, and participation in urban interventions. The results also indicate that citizens can move beyond mere involvement in urban interventions to policy entrepreneurship, influencing policy actions with dedicated interests and goals.</p>