Manufacturing, a branch of industry which accounts for about one-quarter of the world's economic activity, is the application of tools and a processing medium to the transformation of raw materials into finished goods for sale. This effort includes all intermediate processes required for the production and integration of a product's components. Some industries, such as semiconductor and steel manufacturers use the term fabrication instead. The manufacturing sector is closely connected with engineering.

According to some unorthodox economists, manufacturing is a wealth producing sector of an economy, whereas a service sector tends to be wealth consuming. Emerging technologies have provided some new growth in advanced manufacturing employment opportunities in the Manufacturing Belt in the United States. Manufacturing provides important material support for national infrastructure and for national defense.

On the other hand, some manufacturing may involve significant social and environmental costs. The clean-up costs of hazardous waste, for example, may outweigh the benefits. Hazardous materials may expose workers to health risks. Developed countries regulate manufacturing activity with labor laws and environmental laws. In the United States, manufacturers are subject to regulations by the Occupational Safety and Health Administration and the Environmental Protection Agency. In Europe, pollution taxes to offset environmental costs are another form of regulation on manufacturing activity. Labor Unions and craft guilds have played a historic role negotiation of worker rights and wages. Environment laws and labor protections that are available in developed nations may not be available in the third world. Tort law and product liability impose additional costs on manufacturing.

Examples of major manufacturers in the United States include General Motors Corporation, Ford Motor Company, Chrysler, Boeing, and Pfizer. Examples in Europe include France's Airbus and Michelin Tire. Modern proponents of Fair Trade policy and a strong manufacturing base for the U.S. economy inlude economists like Paul Craig Roberts, Ravi Batra, and Lou Dobbs.