Tecumseh's War or Tecumseh's Rebellion are terms sometimes used to describe a conflict in the Old Northwest between the United States and an American Indian confederacy led by the Shawnee chief Tecumseh.

Although the war is often considered to have climaxed with William Henry Harrison's victory at the Battle of Tippecanoe in 1811, Tecumseh's War essentially continues into the War of 1812 and is frequently considered a part of that larger struggle.