Gravity feed is a method that uses Earth's gravity to move something, often a liquid, from one place to another. It is a simple way to move liquids without needing a pump. One common use is supplying fuel to an engine by placing the fuel tank above the engine, such as in motorcycles and lawn mowers. Another example is the carton flow shelving system, which moves items without using pumps.

Ancient Roman aqueducts used gravity to move water into cities. The water was used for drinking, irrigation, and to fill public fountains and baths. In some areas of the world, water systems for remote villages also use gravity. In these systems, water flows from a source to the village because of the vertical distance, or height difference, between the source and the village. Gravity helps the water move, but the flow is slowed by resistance in the pipes. This resistance depends mainly on the pipe's length, diameter, age, and the material it is made from.