Kotetsu may refer to:
- The recurring weapon.
- The character from Final Fantasy Type-0 Side Story: The Reaper of the Icy Blade.
Nagasone Kotetsu was a Japanese swordmaker of the early Edo period. Kotetsu worked as an armorer for some time, but later switched to swordmaking. His swords were known for their great strength and their ability to cut through helmets. However, Kotetsu's swords were often faked, and they were so well faked that even Kotetsu himself is said to have not been able to tell the difference.
"Ko" (虎) means "Tiger" while "Tetsu" (鉄) means "Iron". "虎" alone can also be pronounced "Tora". Literally, Kotetsu means "Tiger Iron" or "Iron of the Tiger" in Japanese.