A cultivator (also known as a rotavator) is a piece of agricultural equipment used for secondary tillage. One sense of the name refers to frames with teeth (also called shanks) that pierce the soil as they are dragged through it linearly. Another sense of the name also refers to machines that use the rotary motion of disks or teeth to accomplish a similar result, such as a rotary tiller.

Cultivators stir and pulverize the soil, either before planting (to aerate the soil and prepare a smooth, loose seedbed) or after the crop has begun growing (to kill weeds—controlled disturbance of the topsoil close to the crop plants kills the surrounding weeds by uprooting them, burying their leaves to disrupt their photosynthesis or a combination of both). Unlike a harrow, which disturbs the entire surface of the soil, cultivators are designed to disturb the soil in careful patterns, sparing the crop plants but disrupting the weeds.

Cultivators of the toothed type are often similar in form to chisel plows, but their goals are different. Cultivators' teeth work near the surface, usually for weed control, whereas chisel plow shanks work deep beneath the surface, breaking up the hardened layer on top.

Small toothed cultivators pushed or pulled by a single person are used as garden tools for small-scale gardening, such as for the household's own use or for small market gardens. Similarly sized rotary tillers combine the functions of a harrow and cultivator into one multipurpose machine.

Cultivators are usually either self-propelled or self drawn as an attachment behind either a two-wheel tractor or four-wheel tractor. For two-wheel tractors, they are usually rigidly fixed and powered via couplings to the tractors' transmission. For four-wheel tractors they are usually attached by means of a three-point hitch and driven by a power take-off . Drawbar hookup is also still commonly used worldwide. Draft-animal power is sometimes still used today, being somewhat common in developing nations although rare in more industrialized economies.

The basic idea of soil scratching for weed control is ancient and was done with hoes or plough for millennia before any larger or more complex equipment was developed to reduce the manual labor and to speed the work. The notion of ganging several hoes together and applying draft animal power to drag them led to harrows, which while newer than the hoe are still quite ancient. In the eighteenth and nineteenth centuries, as the Industrial Revolution developed, a proliferation of cultivator designs proceeded. These new cultivators were drawn by draft animals (such as horses, mules, or oxen) or were pushed or drawn by people, depending on the need and expense.^{[citation needed]}

The powered rotary hoe was invented by Arthur Clifford Howard who, in 1912, began experimenting with rotary tillage on his father's farm at Gilgandra, New South Wales, Australia. Initially using his father's steam tractor engine as a power source, he found that ground could be mechanically tilled without soil-packing occurring, as was the case with normal ploughing. His earliest designs threw the tilled soil sideways, until he improved his invention by designing an L-shaped blade mounted on widely spaced flanges fixed to a small-diameter rotor. With fellow apprentice Everard McCleary, he established a company to make his machine, but plans were interrupted by World War I. In 1919 Howard returned to Australia and resumed his design work, patenting a design with 5 rotary hoe cultivator blades and an internal combustion engine in 1920.

In March 1922, Howard formed the company Austral Auto Cultivators Pty Ltd, which later became known as Howard Auto Cultivators. It was based in Northmead, a suburb of Sydney, from 1927.