Brands constantly challenge each other for market leadership and release new products to outperform their competition (e.g. Coca-Cola vs. Pepsi or Mac vs. PC). Although brand rivalry is a ubiquitous phenomenon that greatly influences consumer behavior, scholars only recently started to examine brand rivalries’ implications for consumer behavior. Prior consumer research related to rivalry focuses on competitive advertising, brand choice making, brand relationships or brand switching. An emerging stream of research specialized on consumer-based implications of brand rivalries investigates the phenomenon from a social identity theory based brand community perspective. However, little research investigates the underlying psychological processes that drive individual consumers to take sides in a brand rivalry. Consumer side-taking can take several forms. Consumers may prefer one brand over its rival brand, possess more favorable perceptions of their brand’s capabilities, counter-argue negative information about their brands and experience a feeling of joy if a rival brand fails (i.e. schadenfreude). Rather than arguing that consumers take sides because of their brand community membership, we propose that side-taking in brand rivalries may be elicited by consumers’ tendencies to stand by their choices. We find that consumers who own brands (especially in the case of ownership-by-choice) are more likely to prefer their owned brand over rival brands, process information regarding their brand more favorably, are more hostile towards their rival brand and show higher levels of schadenfreude. Particularly, we find that consumers show higher levels of schadenfreude if their choice is disconfirmed (e.g. by a comparative product review), especially if their chose brand is perceived to be inferior and less popular. Moreover, these effects are mediated by feelings of self-threat and regret. Finally, we find evidence for the notion that consumer side-taking, and particularly schadenfreude, is a mean of consumer’s self-affirmation.