PurposeFashion brands, including fast and luxury segments, receive harsh criticism for engaging in unethical practices such as poor working conditions and environmental damage. As a result, fashion supply chains are pressured by stakeholders to publicly disclose internal supply chain performance information and to show a high level of supply chain transparency. This paper compares supply chain transparency in fast and luxury fashion in Europe.Design/methodology/approachBy applying the maturity curve of fashion supply chain transparency, developed by Muratore and Marques (2022), the websites of 20 fast and 20 luxury fashion brands were analysed and classified as Opaque, Translucent or Transparent.FindingsDespite its reputation, fast fashion demonstrated higher levels of transparency than luxury fashion. Luxury fashion only performed better in terms of the accessibility of sustainability information. Luxury brands avoided disclosing key transparency information, suggesting that they may be operating in contradiction to that which is inferred on their websites.Originality/valueThe findings of the study shed light on the sustainability credentials of the fashion industry, which has the potential to influence the purchase intentions of consumers, particularly millennials and Generation Z. Implications for practice are developed to highlight how fashion can improve its supply chain transparency.