Promethium is a chemical element with symbol Pm and atomic number 61. It has a number of isotypes, most of which are radioactive and relatively short-lived.
Promethium may also refer to:
- Promethium, a fictional petroleum-based fossil fuel as well as a refined napalm-like substance in Warhammer 40,000
- Promethium, the name of the Mechanic Empire's queen in the fictional universe of Leiji Matsumoto
- Promethium, a fictional metal in stories published by DC Comics
- Promethium (Marvel Comics), a fictional, magical metal in the stories published by Marvel Comics