Industry is the production of an economic good or service within an economy.

Industry is often classified into three sectors: primary or extractive, secondary or manufacturing, and tertiary or services. Some authors add quaternary (knowledge) or even quinary (culture and research) sectors.

Industries can be classified on the basis of raw materials, size and ownership and time.

Industry in the sense of manufacturing became a key sector of production and labour in European and North American countries during the Industrial Revolution, which upset previous mercantile and feudal economies through many successive rapid advances in technology, such as the steel and coal production. It is aided by technological advances, and has continued to develop into new types and sectors to this day. Industrial countries then assumed a capitalist economic policy. Railroads and steam-powered ships began speedily establishing links with previously unreachable world markets, enabling private companies to develop to then-unheard of size and wealth. Following the Industrial Revolution, perhaps a third of the world's economic output is derived from manufacturing industries—more than agriculture's share.