A war hammer is a late medieval weapon of war intended for close combat action, the design of which resembles the hammer. The war hammer consists of a handle and a head. The handle may be of different lengths, the longest being roughly equivalent to the halberd, and the shortest about the same as a mace.

Long war hammers were polearms meant for use against riders, whereas short ones were used in close quarters and on horseback. Later war hammers often had a spike on one side of the head, thus making it a more versatile weapon.