A Tantō (短刀) is a Japanese knife or small sword. It is a smaller version of the Katana, with a blade length of about 15 - 30 cm (6" - 12"). There is a disputed saying about the tantō, wakizashi, and katana stating they are "the same sword in different lengths." The Tantō differs from the others as it was designed primarily as a stabbing instrument, but the edge can be used to slash as well.

Tantō were often interchangeable with Wakizashi, and were preferred on the battlefield due to the fact that they were smaller and got in the way of battle much less. Their use was similar, and they were a samurai's sidearm.

Tantō are forged generally in hira-zukuri, meaning that they have no ridge-line, unlike the shinogi-zukuri shape of a katana. They were generally very thin and therefore would cut soft targets extremely well.