Smithy may refer to:

• Forge, also called a smithy, the workplace of a smith or a blacksmith
• Smith (metalwork), sometimes referred to as a smithy, a person involved in the shaping of metal objects
• Smithy (1924 film), a silent American film starring Stan Laurel
• Smithy (1946 film), an Australian film based on Sir Charles Kingsford Smith's flight across the Pacific Ocean
• Smithy (Mario), the main villain of the video game Super Mario RPG

Smithy is also a documented nickname for a number of notable people and fictional characters:

• Sir Charles Kingsford Smith (1897–1935), Australian pioneer aviator
• W. G. G. Duncan Smith (1914–1996), World War II flying ace
• Mike Smith (television presenter) (born 1955), British television and radio presenter, racing driver, pilot and businessman
• Dale Smith (The Bill), a fictional character on the TV series The Bill
• Neil "Smithy" Smith, fictional character on the TV series Gavin & Stacey played by actor James Corden