Although the phenomenon of lead categories is well-documented in the marketing literature, our understanding of this important store choice factor remains limited. Lead categories are defined as those product categories that are so important for the shopping trip that they influence the consumer’s store choice decision. The purposes of this paper are to offer theoretical bases that explain why lead categories form and to understand how overall images of product quality, selection, and price affect lead category formation. The authors use theories of anchoring effects and automatic cognitive processing to offer theoretical explanations regarding why consumers form lead categories and how overall images of product quality, selection, and price affect lead category formation. Using survey data collected from consumers at two grocery stores, the authors find that positive overall product quality and selection images facilitate lead category formation and that an overall low-price image hinders it.