"Sin" has several different meanings, and can refer to:

• A morally wrong act. See Sin.
• A Sumerian god. See Sin (mythology).
• The sky god and chief deity of the Haida pantheon. See Sin (Haida) .
• An abbreviation of sine in mathematics.
• A Chinese family name 單.
  • Jaime Cardinal Sin
• The Social Insurance Number for Canadians.
• Sin, the primary monster in the game Final Fantasy X.
• The title of a computer game. See Sin (computer game).
• A town in Aargau. See Sin, Switzerland
• A town in Egypt, named in the Bible (Ezek. 30:15). See Sin, Egypt
• A single by Nine Inch Nails. See Sin (Nine Inch Nails).