Based on theories of ambiguity aversion and psychological resource depletion, the current research demonstrates the effect of psychological resource depletion on consumers’ ambiguity aversion behaviors, its underlying mechanism and boundary conditions across four studies. In the contexts of brand choice ( Study 1A) , Ellsberg's two-color-ball decision ( Study IB) and price premium ( Study 1C) , we find that psychological resource depletion enhances ambiguity aversion. The effect of psychological resource depletion on ambiguity aversion is mediated by the willingness to process the competing possibilities associated with ambiguity ( Study 2) . When the outcome becomes more ambiguous ( has a wider range of possibilities , Study 3) or consumers have more product knowledge ( require less psychological resources to process ambiguity, Study 4) , the influence of resource depletion on ambiguity aversion strengthens or attenuates.