This paper examines why Western Australia's Integrated Fisheries Management (IFM) policy was adopted, its development, achievements, lessons learned and future directions. Adopted in 2004, IFM aims to achieve and maintain fish resource sustainability through optimal catch share arrangements between competing users. It involves setting an allowable harvest level for each resource, using an independent allocation committee process to allocate explicit catch shares for commercial, recreational and customary sectors, and monitoring sectoral catch. IFM provides guidance for managing each sector within its catch share, providing access to that share, and developing reallocation mechanisms to transfer sectoral catch shares. The three most important multi-sector resources, western rock lobster, Panulirus cygnus George, metropolitan Roe's abalone, Haliotis roei Grey, and west coast demersal scalefish, have undergone the allocation process. The first two are operational while the third is almost complete. Allocation outcomes demonstrate the need to account for each sector's catch, with credible scientific data to underpin decision-making, independent transparent allocation processes, robust sectoral representation, workable reallocation mechanisms and management arrangements to ensure that all sectors can access their allocated share. IFM generates fair decisions for optimal resource use to reduce intersectoral conflict and provide better community outcomes, with wide applicability across other jurisdictions.