The topic of rivalry is a favorite in sport popular culture. Fans, media members, and participants frequently discuss who is a rival team, what constitutes a rivalry, and what rivalries are most relevant in sport. For example, if one turns the television to a sport channel or visits popular sport media websites, they will almost certainly be exposed to a story, highlights, or discussion about rivalry. The phenomenon is so popular among sport fans that major television and media outlets have labeled portions of seasons accordingly (e.g., college football’s Rivalry Week typically runs the last regular season week when most traditional rival teams play and Major League Soccer has recently started to promote Rivalry Week two times during its season). However, given the attention the topic receives from fans and the popular media, academic research only recently began to focus on understanding and explaining this topic. The purpose of this special issue is to highlight the phenomenon, and present empirically driven ideas that can help academicians and practitioners better understand the marketing implications of rivalry in sport.