Uncertainty is an important concept within consumer behavior which to date is under-theorized, especially in relation to important downstream variables such as information search intention and purchase intention, and can therefore lead to a loss of utility. The authors propose a new multidimensional conceptualization of consumer uncertainty and develop a theoretical model of uncertainty within two consumer behavior contexts, namely avoidance of sweatshop apparel and avoidance of food additives. Drawing on literature-based insights as well as qualitative research and Expected Utility Theory, the authors develop hypotheses that offer insight into the potential antecedents (ambiguity and credibility) and consequences (search intention and purchase intention) of uncertainty. Using survey data, the authors test the hypotheses, finding strong support for many relationships hypothesized. Research and managerial implications are discussed. © 2011 Wiley Periodicals, Inc.