Header may mean:

• Header (information technology), supplemental data at the beginning of a data block

• Header file, a text file used in computer programming (especially in C or C++)

• Page header, in printing or typography the material separated from the main body and appears at the top of a page

• An exhaust manifold in automotive engineering

• A lintel in building construction

• An electronic component which supplies a physical interface (usually a connector of some type) to a group of signal lines or PCB traces.

• Use of the player's head to deflect the ball in association football (soccer)

• A competitor in the team roping rodeo event who specializes in roping a steer's head

• A herding dog with a specific method of interacting with its flock