This study investigated social-media-based anti-sponsor-brand communities and their impacts, not only on the sponsoring brand but also on the sponsored club and the sport itself. Guided by balance theory and social identity theory, the authors conducted a qualitative study of 2 distinctive, prototypical Facebook-based anti-sponsor-brand communities of teams from the German Football League (Bundesliga). The results reveal common findings for both cases, including members’ motivation to oppose a sponsor and, at the same time, to protect the sport. However, the communities differ in terms of their members’ relationships to the club. This results in different consequences for the sponsor and club brands, as well as for other actors in the sponsorship network. To managers of clubs, sponsors, and sport-governing bodies, the authors suggest concerted strategies like image campaigns and interaction with anti-sponsor-brand communities as responses to different community motivations.