The Indonesian fashion industry has continuously been growing since the last decade. However, the fashion industry practices produce negative environmental and social consequences. To overcome these issues, the Indonesian government encourages Indonesian fashion industries to adhere to sustainable practices to maintain and improve competitiveness in the global market since it is believed to be the future of the business. Therefore, it is necessary to determine the main indicators of sustainable practices in the fashion industry to measure the performance of a sustainable supply chain system. This study aims to develop a set of relevant key performance indicators (KPIs) in implementing a sustainable supply chain for the Indonesian fashion industry. Initially, this study reviewed the existing sustainability indicators to develop an initial short-list of indicators. Then, indicators were assessed and validated by a group of eight experts consisting of five industry representatives, a government official, a non-government organization leader, and an academic through a questionnaire. This study utilized content validity index (CVI) methods to get consensus indicators from all experts. From this study, 21 indicators were validated and could be further used by the fashion industries to improve their sustainability performance.