In many European cities, urban experimentation is increasingly preferred as a method for testing and disseminating innovations that might ignite a transformation toward more sustainable cities. By both academics and practitioners, these experiments tend to be approached as relatively neutral initiatives through which plural urban stakeholders willfully collaborate, while their success is seen as above all dependent on effective management. For this reason, the political nature of urban experiments, in the sense that they entangle different and often contending stakeholders in their innovation processes, remains relatively unarticulated in both practice and the academic literature. Building on the urban experimentation literature and political theory, this conceptual paper argues that the depoliticization of experimental initiatives is especially problematic for unleashing their transformative potential, which requires revealing the existing power-relations and biases keeping the status-quo in place and negotiability of radical alternatives. From this perspective, the paper sketches out four ideal-typical trajectories for experiments as related to their (de)politicization; optimization, blind leap, antagonistic conflict and transformation. Bringing insights from political theory to bear on the urban experimentation literature, we proceed to hypothesize the implications of our ideal-types for urban experiments’ transformative capacities. The paper closes by presenting a future research and policy agenda.