This article critiques the mineral resource policy harmonisation strategies adopted by supranational institutions in West Africa, focusing on local content/procurement and fiscal policy/taxation. Although minerals are sometimes defined to cover both mining and oil and gas, the article focuses on policies related to mining. It views West Africa’s mineral resource policy harmonisation strategies relating to local content and taxation as an attempt to standardise the rules and practices among individual States. Standardisation is particularly strong within the West African Economic and Monetary Union, which requires its member States to domesticate its harmonisation texts without modification. The article argues for a shift from enacting binding supranational rules governing substantive issues (such as the type of local content requirements to be adopted and the fixing of tax and royalty rates) towards rules that promote inter-State cooperation and sharing of information. This would give States sufficient latitude to tailor supranational initiatives to local needs.