A flatcar (also spelled as flat car) is a piece of railroad rolling stock that consists of an open, flat deck on a pair of bogies. The deck of the car can be made of wood or steel, and the sides of the deck can include pockets for stakes or tie-down points to secure loads.

Flat cars are used for loads that are too large or cumbersome to load in enclosed cars such as boxcars. They are also often used to transport containers or trailers in intermodal shipping.