The division of labour is the separation of the tasks in any economic system or organisation so that participants may specialise (specialisation). Individuals, organisations, and nations are endowed with or acquire specialised capabilities, and either form combinations or trade to take advantage of the capabilities of others in addition to their own. Specialised capabilities may include equipment or natural resources as well as skills. Training and combinations of equipment and other assets acting together are often important. For example, an individual may specialise by acquiring tools and the skills to use them effectively just as an organisation may specialise by acquiring specialised equipment and hiring or training skilled operators. The division of labour is the motive for trade and the source of economic interdependence.

An increasing division of labour is associated with the growth of total output and trade, the rise of capitalism, and the increasing complexity of industrialised processes. The concept and implementation of division of labour has been observed in ancient Sumerian (Mesopotamian) culture, where assignment of jobs in some cities coincided with an increase in trade and economic interdependence. Division of labour generally also increases both producer and individual worker productivity.

After the Neolithic Revolution, pastoralism and agriculture led to more reliable and abundant food supplies, which increased the population and led to specialisation of labour, including new classes of artisans, warriors, and the development of elites. This specialisation was furthered by the process of industrialisation, and Industrial Revolution-era factories. Accordingly, many classical economists as well as some mechanical engineers, such as Charles Babbage, were proponents of division of labour. Also, having workers perform single or limited tasks eliminated the long training period required to train craftsmen, who were replaced with less-paid but more productive unskilled workers.

In Plato's Republic, the origin of the state lies in the natural inequality of humanity, which is embodied in the division of labour:

Well then, how will our state supply these needs? It will need a farmer, a builder, and a weaver, and also, I think, a shoemaker and one or two others to provide for our bodily needs. So that the minimum state would consist of four or five men....

— Republic (Penguin Classics ed.), p. 103

Silvermintz (2010) noted that "Historians of economic thought credit Plato, primarily on account of arguments advanced in his Republic, as an early proponent of the division of labour." Notwithstanding this, Silvermintz argues that "While Plato recognises both the economic and political benefits of the division of labour, he ultimately critiques this form of economic arrangement insofar as it hinders the individual from ordering his own soul by cultivating acquisitive motives over prudence and reason."

Xenophon, in the 4th century BC, makes a passing reference to division of labour in his Cyropaedia (a.k.a. Education of Cyrus).