An assembly line is a manufacturing process which is a very important part of industry.

In an assembly line, parts are added to a product in a sequence. Each worker and machine does one part, and the parts are put together to make the finished object. This makes a product much faster than with handcrafting-type methods, where one person made the whole object.

The division of labour was discussed by Adam Smith in his book The Wealth of Nations (1776). He used the manufacture of pins as an example of increasing productive efficiency.