An increasing number of textile firms are adopting sustainability strategies for achieving long-term competitive advantage. In this paper, a new decision-making process for the textile sector, exploiting the Organisational Life Cycle Assessment methodology, is proposed. It provides a management system able to support companies in monitoring and evaluating environmental performances with a dynamic perspective and identify which activity and/or mechanical plant needs to be improved or changed in order to reduce the environmental impact, enabling cost savings, and at the same time, developing the business case for sustainability. In particular, for each Organisational Life Cycle Assessment phase, an operational tool was established. The tools were developed both by reviewing specific literature and by conducting in-depth semi-structured interviews in six textile companies. Across firms, informants included the Managing Director, the Plant Manager, shop floor supervisors and workers, and representatives from Corporate Social Responsibility Committee, Manufacturing, Quality, and Accounting. Additionally, direct observation (e.g., plant tours) was also used as data collection method. A case study of a spinning company reveals the potential benefits of this decision-making process.