Class 3 may refer to:
BR Standard Class 3 2-6-0, British steam locomotive BR Standard Class 3 2-6-2T, British steam locomotive Classes of United States senators L&YR Class 3, British 4-4-0 steam locomotive SCORE Class 3, off-road racing trucks The third class in terms of hiking difficulty in the Yosemite Decimal System A class in US truck classification Class 3, in the electrical Appliance classes A contribution class in the National Insurance system in the UK
See also Class III (disambiguation) Class 03 (disambiguation) NSB El 3, Norwegian electric locomotive NSB Di 3, Norwegian diesel locomotive Type 3 (disambiguation)