The McCormick-Deering OS-6 is an orchard/vineyard tractor produced from 1944 to 1953 by McCormick-Deering in Rock Island, Illinois, USA. It features a 4.1L 4-cylinder liquid-cooled gasoline engine by International Harvester, a 5-speed gear transmission with 5 forward and 1 reverse gears, and two-wheel drive with an open operator station. The OS-6 variant is an orchard model without full sheet metal. It is part of a series including the W-6, O-6, ODS-6 diesel, I-6 industrial, and ID-6 diesel industrial models.