This article documents single-option aversion, an increase in consumers. desire to search when faced with a single option. This effect can lead to a product being chosen more often when competing alternatives are included in the choice set, contrary to various rational models of search, as well as to recent research on choice conflict showing that additional options can lead to higher deferral rates. A series of lab studies document this effect, differentiate it from other context effects, and test some of its boundary conditions. The results suggest that single-option aversion is not driven by the information provided by the additional options, that the desire to search is critical for this effect to occur, and that the effects of single-option aversion are not limited to the immediate choice set. These results have both practical and theoretical implications for the understanding of consumer search and choice deferral.