Much research documents that uncertainty is an important factor in the social influence process. We argue that there are two senses in which uncertainty plays a role. First, task uncertainty is a necessary but variable condition for social influence to occur. Second, uncertainty reduction is a mechanism producing social influence. We discuss how tasks can vary in the level of uncertainty they entail and how this impacts the mechanisms resulting in social influence. In this context, we predict that task uncertainty moderates social influence and that uncertainty reduction mediates it. We experimentally test our predictions in the status-to-social-influence process using standard means of studying social influence. Inconsistent with prior work, we do not find that task uncertainty is a moderator, but we do find evidence that uncertainty reduction functions as a mediator. Further, we find that the mediated effect is contingent on task uncertainty.