A krewe is a social organization that stages parades and/or balls for the Carnival season. The term is best known for its association with Mardi Gras celebrations in New Orleans, but is also used in other Carnival celebrations throughout Louisiana and along the Gulf of Mexico, such as the Gasparilla Pirate Festival in Tampa, Florida, Springtime Tallahassee, and Krewe of Amalee in DeLand, Florida with the Mardi Gras on Mainstreet Parade as well as in La Crosse, Wisconsin and at the Saint Paul Winter Carnival.

Mardi Gras is the final day of Carnival ; it thus falls on the day before the beginning of Lent on Ash Wednesday. Mardi Gras is French for "Fat Tuesday", reflecting the practice of the last night of consuming rich, fatty foods in preparation for the Christian fasting season of Lent, during which the consumption of such foods is avoided.