Sharing economy (SE) platforms are increasingly providing an effective means of connecting providers and users of secondhand goods. While media seem to emphasize that the trend of selling/buying secondhand has been growing due to the consolidation and development of peer‐to‐peer (P2P) sharing platforms, a comprehensive identification of the antecedents of buying secondhand on SE platforms is virtually missing. This study addresses this gap by (a) identifying different sets of motivations and attitudes leading consumers to adopt SE platforms for secondhand buying and (b) testing a model on a sample of UK consumers in the context of P2P sharing platforms for secondhand clothing. This study reveals that there are three major antecedents of consumers' attitude towards buying secondhand clothes on P2P–SE platforms: perceived sustainability, economic motivations, and taking a distance from the consumption system. Perceived sustainability and economic motivations influence positively attitude toward buying secondhand, as well as motivations in the form of distance from the consumption system. Attitude toward buying secondhand is positively influenced also by distance from the system and, in turn, has a strong positive influence on behavioral intention to buy secondhand clothes. Moreover, past experience of buying secondhand online has a positive moderating effect on the relationship between perceived sustainability and distance from the consumption system.