Do responsibility voids exist? That is, are there situations in which the group is collectively morally responsible for some outcome although no member can be held individually morally responsible for it? To answer these questions, I draw a distinction between competitive and cooperative decision contexts based on the team-reasoning account of cooperation. Accordingly, I provide a reasoning-based analysis of cooperation, competition, moral responsibility, and, last, potential responsibility voids. I then argue that competitive decision contexts are free of responsibility voids. The (...) conditions for the existence of responsibility voids in cooperative decision contexts depend on the type of uncertainty the group faces, either external or coordination uncertainty. (shrink)