Mass production, also known as series production, series manufacture, or continuous production, is the production of substantial amounts of standardized products in a constant flow, including and especially on assembly lines. Together with job production and batch production, it is one of the three main production methods.

The term mass production was popularized by a 1926 article in the Encyclopædia Britannica supplement that was written based on correspondence with Ford Motor Company. The New York Times used the term in the title of an article that appeared before the publication of the Britannica article.

The idea of mass production is applied to many kinds of products: from fluids and particulates handled in bulk (food, fuel, chemicals and mined minerals), to clothing, textiles, parts and assemblies of parts (household appliances and automobiles).

Some mass production techniques, such as standardized sizes and production lines, predate the Industrial Revolution by many centuries; however, it was not until the introduction of machine tools and techniques to produce interchangeable parts were developed in the mid-19th century that modern mass production was possible.

Mass production involves making many copies of products (Mainly done through machines), very quickly, using assembly line techniques to send partially complete products to workers who each work on an individual step, rather than having a worker work on a whole product from start to finish. The emergence of mass production allowed supply to outstrip demand in many markets, forcing companies to seek new ways to become more competitive. Mass production ties into the idea of overconsumption and the idea that we as humans consume too much.

Mass production of fluid matter typically involves piping with centrifugal pumps or screw conveyors (augers) to transfer raw materials or partially complete products between vessels. Fluid flow processes such as oil refining and bulk materials such as wood chips and pulp are automated using a system of process control which uses various instruments to measure variables such as temperature, pressure, volumetric and level, providing feedback.

Bulk materials such as coal, ores, grains and wood chips are handled by belt, chain, slat, pneumatic or screw conveyors, bucket elevators and mobile equipment such as front-end loaders. Materials on pallets are handled with forklifts. Also used for handling heavy items like reels of paper, steel or machinery are electric overhead cranes, sometimes called bridge cranes because they span large factory bays.

Mass production is capital-intensive and energy-intensive, for it uses a high proportion of machinery and energy in relation to workers. It is also usually automated while total expenditure per unit of product is decreased. However, the machinery that is needed to set up a mass production line (such as robots and machine presses) is so expensive that in order to attain profits there must be some assurance that the product will be successful.