Kenworth Truck Company is an American truck manufacturer. Founded in 1923 as the successor to Gersix Motor Company, Kenworth specializes in production of heavy-duty (Class 8) and medium-duty (Class 5–7) commercial vehicles. Headquartered in the Seattle suburb of Kirkland, Washington, Kenworth has been a wholly owned subsidiary of PACCAR since 1945,^[2] operating alongside sister company (and marketplace rival) Peterbilt Motors.

Kenworth marked several firsts in truck production; the company introduced a raised-roof sleeper cab, and the first heavy-duty truck with an aerodynamically optimized body design.^[3] The Kenworth W900 has been produced continuously since 1961, serving as one of the longest production runs of any truck in automotive history. The K100 was also released in 1961.