This article investigates a sequential phenomenon that can only occur in multiperson interaction: the alignment of two or more participants into teams in the course of a disagreement. The database of the study consists of videotaped committee meetings. The article concentrates on two issues. In the first place, it discusses the characteristics of the turns generating collective disagreement in institutional committee meetings and the design of the first dissenting turns. It demonstrates that alliances are typically formed after matter-of-fact statements, stance-takings, and proposals which, in one way or another, call for disagreement in this setting. The relevance of disagreement is further reinforced by the fact that the first and the second dissenting turn are often produced very rapidly, often in overlap with each other. Common devices used in the first alignment turns are collaborative completion and repetition of the elements of the prior turn, but alliances can also be initiated through non-verbal devices such as head-shakes. Secondly, the article shows that the alliances accomplish four main types of tasks in these interactions. First, they correct statements which seem to need correction on the basis of the knowledge or experience of the participants. Second, the alliances function as a controlling organ, adjusting or moderating a categorical or one-sided stance expressed by a co-participant and, third, alliances are set up in decision-making situations. Fourth, acting in alliance can be rewarding for the members as a social activity. This sometimes tempts the participants to engage in arguments that do not necessarily deal with issues relevant from the point of view of the institutional goals of the committee. Such activities occasionally lead to an intervention by the chairperson and, accordingly, make visible the norms and limits of the institutional setting.