We report a series of experimental studies that investigate the influence of a competition on noncompetitors who do not participate in it but are aware of it. Our work is highly relevant across many domains of social life where competitions are prevalent, as it is typical in a competition that the competitors are far outnumbered by these noncompetitors. In our field experiment involving pay-what-you-want entrance at a German zoo (n = 22,886), customers who were aware of a competition over entrance payments, but did not participate in it, paid more than customers who were unaware of the competition. Further experiments provide confirmatory and process evidence for this contagion effect, showing that it is driven by heightened social comparison motivation due to mere awareness of the competition. Moreover, we find evidence that the reward level for the competitors could moderate the contagion effect on the noncompetitors. Even if an individual does not participate in a competition, their behavior can still be influenced by it, and this influence can change with the characteristics of the competition in an intriguing way.