Peer-to-peer networks and protocols have inspired new ideas and ideologies about governance, with the aim of using technology to enable horizontal and decentralized decision-making at scale. This article introduces the concept of “dissensus” from political theory to debates about peer governance in online communities. Dissensus describes the emergence of incompatible differences. Among peer-to-peer technologies, blockchain stands out as a set of ideas that explicitly seek to resolve dissensus through consensus protocols. In this article, we propose dissensus as a “protocol” for foregrounding the often sidelined yet productive aspects of incompatible differences. The concept highlights that there might not always be consensus about a consensus algorithm, and that indeed, dissensus is the precondition for new possibilities and perspectives to emerge. We discuss the concept in relation to the histories of governance ideas in blockchain, namely, a “materialist,” “design,” and “emergent” approach. We then describe moments of dissensus in practice through two cases of online communities, Genesis DAO and Ouishare, discussing their different ways of recognizing and navigating dissensus. Finally, we give a critical overview of consensus algorithms, voting, staking, and forking as the mechanisms that make out blockchain governance ideologies. In conclusion, we argue that dissensus can serve as a useful concept for pointing attention to governance as it is conducted in practice, as historically and culturally specific practices, rather than as a problem to be solved through supposedly universal mechanisms.