Heavy equipment or heavy machinery refers to heavy-duty vehicles, specially designed for executing construction tasks, most frequently ones involving earthwork operations or other large construction tasks. Heavy equipment usually comprises five equipment systems: implementation, traction, structure, power train, control and information.

Heavy equipment has been used since at least the 1st century BCE when the ancient Roman engineer Vitruvius described a crane in De architectura when it was powered via human or animal labor.

Heavy equipment functions through the mechanical advantage of a simple machine, the ratio between input force applied and force exerted is multiplied, making tasks which could take hundreds of people and weeks of labor without heavy equipment far less intensive in nature. Some equipment uses hydraulic drives as a primary source of motion.

The term "plant" is used to refer to any mobile type of heavy machinery.

Until the 19th century and into the early 20th century heavy machines were drawn under human or animal power. With the advent of portable steam-powered engines the drawn machine precursors were reconfigured with the new engines, such as the combine harvester. The design of a core tractor evolved around the new steam power source into a new machine core traction engine, that can be configured as the steam tractor and the steamroller. During the 20th century, internal-combustion engines became the major power source of heavy equipment. Kerosene and ethanol engines were used, but today diesel engines are dominant. Mechanical transmission was in many cases replaced by hydraulic machinery. The early 20th century also saw new electric-powered machines such as the forklift. Caterpillar Inc. is a present-day brand from these days, starting out as the Holt Manufacturing Company. The first mass-produced heavy machine was the Fordson tractor in 1917.