Uncertainty Reduction Theory (URT) proposes that individuals have a need to reduce uncertainty and that elevated levels of uncertainty are associated with relational dissatisfaction. Research on cross-sex friendships suggests that these relationships may be characterized by elevated levels of uncertainty and topic avoidance. This investigation addresses the role of uncertainty as a theoretical construct that may be useful for explaining behavior in cross-sex friendships. Specifically, we address the relationship between uncertainty and topic avoidance, and compare cross-sex friendships and dating relationships on these variables. The results significantly extend past research on cross-sex friendships and suggest that uncertainty may often be tolerated in cases where the expected information is undesirable.