Harley-Davidson (NYSE: HOG, formerly HDI[3]), often abbreviated H-D or Harley, is an American motorcycle manufacturer. Founded in Milwaukee, Wisconsin, during the first decade of the 20th century, it was one of two major American motorcycle manufacturers to survive the Great Depression.[4] Harley-Davidson also survived a period of poor quality control and competition from Japanese manufacturers.[5]

The company sells heavyweight (over 750 cc) motorcycles designed for cruising on the highway. Harley-Davidson motorcycles (popularly known as "Harleys") have a distinctive design and exhaust note. They are especially noted for the tradition of heavy customization that gave rise to the chopper style of motorcycle.[6] Except for the modern VRSC model family, current Harley-Davidson motorcycles reflect the styles of classic Harley designs. Harley-Davidson's attempts to establish itself in the light motorcycle market have met with limited success and have largely been abandoned since the 1978 sale of its Italian Aermacchi subsidiary.

Harley-Davidson sustains a loyal brand community which keeps active through clubs, events, and a museum. Licensing of the Harley-Davidson logo accounts for almost 5% of the company's net revenue.