A Tomb of the Unknown Soldier or Tomb of the Unknown Warrior is a monument dedicated to the services of an unknown soldier and to the common memories of all soldiers killed in war. Such tombs are located in many nations and are usually high-profile national monuments. Throughout history, many soldiers have died in war with their remains being unidentified. Following World War I, a movement arose to commemorate these soldiers with a single tomb, containing the body of one such unidentified soldier.

A tomb or sepulcher is a repository for the remains of the dead. It is generally any structurally enclosed interment space or burial chamber, of varying sizes. Placing a corpse into a tomb can be called immurement, although this word mainly means entombing people alive, and is a method of final disposition, as an alternative to cremation or burial.