Marketers are charged with the responsibility of attracting consumers and encouraging loyalty for their brands. Double jeopardy, a marketing law observed across numerous product and service settings, contends that loyalty is largely influenced by a brand's market share. There have been suggestions that sport may be one of the few areas immune to such effects, providing researchers with an opportunity to test how sport brand loyalty may be impacted by market share. The current research capitalises on this opportunity by assessing the effects of market share on attitudinal loyalty reported by a sample of 794 Australian sport fans. ANOVA tests revealed that fans of high market share brands displayed higher levels of attitudinal loyalty towards their favourite teams in comparison to small market share team fans. Further tests revealed that differences existed in terms of the brand association perceptions held by high and small market share team fans, and how these contributed to predicting attitudinal loyalty. Consequently, sport marketers should be cognisant of double jeopardy effects when evaluating sport brands and formulating marketing strategies, though future research is needed to determine the full applicability of double jeopardy within the sport context.