The purpose of this dissertation is to examine the phenomenon of “consumer competition.” The overarching objective is to help researchers and marketing practitioners understand how the phenomenon is created, how consumers experience competition, and to begin to inspect its effects. Consumer competition is defined as the active processes of striving against others for the acquisition of a consumption object. To date, this phenomenon has been under-researched, despite its prevalence in many marketing and consumer-related domains. An extensive literature synthesis provides the foundation for understanding competition and competitiveness in general from a multi-disciplinary perspective. Based on the synthesis of literature and respective theory, this research contends that a scarcity effect contributes to consumer competition. It also contends that competitive situations may be purposely created by retailers, who may or may not understand its benefits and/or consequences to the people involved. This dissertation examines the phenomenon in two manners. First, an exploratory study seeks to enrich our understanding of how consumers experience competition in a retail setting. Employing the grounded theory method, researching participants engaged in a competitive shopping context offers insight into the meaning of competition, the motivation for competing, the experiential components of competing, and the outcome of participating in a competitive shopping situation. Second, an experiment tests the influence of scarcity messages on consumers’ perceptions of a competitive purchase situation and the related purchase interest. The results of the research are multi-faceted. It provides managerial insight into an effect of scarcity not yet examined: perceptions regarding the competitive nature of a purchase situation. This is an important distinction given the influence of perceptions on behavior. It also provides insight to enrich our understanding of how consumers engage in competitive shopping behavior and how they reflect on competitive situations in the retail domain.