The Amalgamated Engineering Union (AEU), originally known as the Amalgamated Society of Engineers, was an Australian trade union which existed between 1852 and 1973.

The first Australian branch of the Amalgamated Society of Engineers was formed in Sydney in 1852 by 27 members of the British union who had emigrated to Australia following a lockout in Britain.

While the Australian section was the first overseas branch of the union to be formed, several others were established over the course of the 19th century, including in Canada, South Africa, New Zealand and the United States.

[1] In 1890 a breakaway group formed the Australasian Society of Engineers, dissatisfied with the union being controlled from Britain.

[3] The ASE was famous for its involvement in the landmark 1920 High Court of Australia case, Amalgamated Society of Engineers v Adelaide Steamship Co. Ltd., more popularly known as the Engineers' case, which overturned the doctrine of implied intergovernmental immunities, significantly altering the balance of power in Australian federalism.