This study aims to examine the influence of attitudes on customers’ intention to participate in online fashion sharing. A framework was proposed to investigate the relationships between consumer motivation, consumer attitude, and purchase intention in the manner of adopting a fashion-sharing platform. Consumer motivations are divided into three categories: utilitarian, hedonic, and ecological. The moderating effects of product replacement cycle (PRC) on consumer attitude and purchase intention are also investigated. Data collection was developed using a web-based survey where 180 consumer respondents from South Korea participated. The results of our analysis indicate that consumers’ hedonic and ecological motivations are positively related to favorable consumer attitudes, even when consumers’ utilitarian motivation is denied. Consumer attitude is also positively related to purchase intention in the fashion-sharing platform. A moderating effect of PRC is recorded between consumer attitude and purchase intention based on high and low PRC, as well as the effect of ecological motivation and consumer attitude on high PRC. This study enhances knowledge of consumer motivational factors in a fashion-sharing platform and provides insights for service providers to help them improve their target marketing.