<p>In this paper, we propose a conceptual framework to understand and examine the argumentative content in multimodal protest. Protests arise in public controversies when people are dissatisfied with the way institutions deal with problems in society, and when conventional routes for addressing these issues are deemed problematic, especially for the powerless. Protest typically involves not only verbal expressions, but also the use of images, and bodily performances. While protest and other forms of activism are extensively explored from various perspectives, its argumentative role is understudied. In this paper, we show that protest not only contributes to public controversies through intervention (e.g. social or cognitive pressure), but also through communication. The argumentative value lies in the (multimodal) communicative dimension of protest: we can understand protest as a communicative act that uses multimodal means to express disapproval about something and to advocate a remedy. We argue that protest contributes arguments to a public controversy by (1) expressing a core argument that addresses potential critical reactions to the claims intrinsic to any protest, and by (2) providing, what we call, proto-arguments, i.e. pieces of information that the audience can use to argue in support of the protest at future occasions. Using the case study of Extinction Rebellion’s highway blockades in the Hague in the Netherlands, we illustrate the pattern of the core argument of protest and three types of proto-arguments. By broadening the scope of argumentation, we invite argumentation scholars to take multimodal protest seriously.</p>