This research adopts a consumer focus in examining the impact of perceived legitimacy of sharing economy platforms on attitude and behavioural intention in the accommodation sector. By investigating tourist adoption of sharing economy platforms from a legitimacy perspective, this research differs from past studies which focused on characteristics of new services to predict adoption. Results show that (1) tourists evaluate legitimacy through comparisons with traditional offers in the accommodation sector rather than with other sharing economy offers, (2) lack of legitimacy has a negative effect on guest behavioural intentions and (3) this effect is moderated by relativism. Even though sharing economy platforms' commercial success may imply that they are enjoying a high level of legitimacy in the eyes of tourists, our results suggest that tourists act as societal actors and that the legitimacy issues raised by the sharing economy are relevant to them and inform their decisions.