A bulldozer is a large and heavy tractor equipped with a substantial metal plate (termed a blade) used to push large quantities of soil, sand, snow, rubble, or similar material during construction or conversion work and typically equipped at the rear with a claw -like device (termed a ripper) to loosen densely compacted materials. Most bulldozer tractors are continuous tracked, also termed a crawler.

Bulldozers can be found on a wide range of sites, mines and quarries, military bases, heavy industry factories, engineering projects, and farms.

The word "bulldozer" correctly refers to only a tractor fitted with a dozer blade. The word is sometimes used inaccurately for other similar construction vehicles such as a front loader.

Typically, bulldozers are large and powerful tracked heavy equipment. The tracks give them excellent ground-holding capability and mobility through very rough terrain. Wide tracks help distribute the bulldozer's weight over a large area (decreasing ground pressure), thus preventing it from sinking in sandy or muddy ground. Extra-wide tracks are known as swamp tracks or low ground pressure tracks. Bulldozers have transmission systems designed to take advantage of the track system and provide excellent tractive force.

Because of these attributes, bulldozers are often used in road building, construction, mining, forestry, land clearing, infrastructure development, and any other projects requiring highly mobile, powerful, and stable earth-moving equipment.

Another type of bulldozer is the wheeled bulldozer, which generally has four wheels driven by a four-wheel-drive system and has a hydraulic, articulated steering system. The blade is mounted forward of the articulation joint, and is hydraulically actuated.

The bulldozer's primary tools are the blade and the ripper.