The Federated Moulders' (Metals) Union of Australia (FMMUA) was an Australian trade union which existed between 1899 and 1983. It represented moulders – skilled tradesmen who fabricated the moulds for casting metal products in foundries. In spite of only organising within a single skilled occupation, which kept total membership low, the vital position of moulders in major industries such as mining, manufacturing and the railways, ensured that the union remained industrially powerful with a reputation for being highly militant.