Tengen may refer to:
- Tengen (Go), the center point on a Go board, and the name of a Go competition in Japan
- Tengen (city), a city in Baden-Württemberg, Germany
- Tengen (company), a defunct video game publisher and developer
- Tengen (era), the Japanese era name for the years 978–983
- Tengen Toppa Gurren Lagann, a 2007 anime series by Gainax
- Tian yuan shu, in Japanese tengenjutsu (天元術), a method of algebra in Chinese and Japanese mathematics
- Tengenjutsu (fortune telling) (天源術), a Japanese fortune telling method