A pusher, pusher craft, pusher boat, pusher tug, or towboat, is a boat designed for pushing barges or car floats. In the United States, the industries that use these vessels refer to them as towboats. These vessels are characterized by a square bow, a shallow draft, and typically have knees, which are large plates mounted to the bow for pushing barges of various heights. These boats usually operate on rivers and inland waterways. Multiple barges lashed together, or a boat and any barges lashed to it, are referred to as a "tow" and can have dozens of barges. Many of these vessels, especially the long distance, or long haul boats, include living quarters for the crew.

Barge often refers to a flat-bottomed inland waterway vessel which does not have its own means of mechanical propulsion. The first modern barges were pulled by tugs, but on inland waterways, most are pushed by pusher boats, or other vessels. The term barge has a rich history, and therefore there are many other types of barges.