Third Empire may refer to:
- Third Bulgarian Empire, occasionally used to describe the Kingdom of Bulgaria (1908–1946)
- Third German Empire or Third Reich, a common name for Nazi Germany (1933–1945)
- Das Dritte Reich ("The Third Empire"), a 1923 novel by A. Moeller-Bruck which influenced the Nazi Party
- Third Persian Empire, sometimes used to describe the Sassanid Empire (ca. AD 224–651)
- 3rd Empire Awards, film awards held in 1998