An edger (also known as a lawn edger or stick edger) is a garden tool used to cleanly separate a lawn from a walkway or other paved surface, such as a concrete sidewalk or asphalt path. Edgers may be manual or automated, typically employing a small two-stroke gasoline motor or an electric motor. An edger enables a user to create a clear separation between the lawn and the walkway. It helps to impart a finished appearance that is neater than can be achieved by merely mowing over the border of the lawn and walkway (which frequently permits tufts of low-growing grass to hang over onto the walkway, resulting in an irregular or ragged appearance).

In operation, a manual edger usually includes a broad hemispherical blade attached to an elongated handle, which the operator uses to drive the blade into the turf directly alongside the hard surface. In addition, the blade may have a flat top to allow the operator to step on the blade, driving it deep into the lawn and turf in order to clear a space between the lawn and the hard surface. In contrast, powered edgers may operate on any of a variety of methods, such as rotating wheel blades or thrashing wheels, which also operate to define a clear separation between a lawn and a hard surface.