Given that marketing managers are taught the significance of predicting and responding to competitors' actions, comparing their firms' strategies to those of competitors, and developing sustainable competitive advantages over competitors, the task of identifying competitors emerges as pivotal for effective marketing strategy development. However, a notable challenge lies in the diverse interpretations of what defines a competitor among strategists. This article explicates the nature of competitors by drawing on resource-advantage theory and its focus on market segments. Specifically, it focuses on market segmentation strategy as a mechanism to examine what constitutes a 'competitor'. In addition, it outlines an approach that can be used to identify competitors.