Yamauchi or Yamanouchi (やまうち lit. "inside mountains") is a Japanese surname. Either name is written in kanji as 山内 while Yamanouchi can also be written as 山ノ内.
Notable people with this surname include:
- Yamanouchi Toyoshige, 15th feudal lord of the Tosa domain
- Yamauchi Kazutoyo, first feudal lord of the Tosa domain
- Kenji Yamanouchi, eponymous founder of Yamanouchi Pharmaceutical Co., now part of Astellas Pharma
- Edwin M. Yamauchi, historian and biblical scholar
- Fusajiro Yamauchi, founder of Nintendo
- Hiroshi Yamauchi, former president of Nintendo
- Kazunori Yamauchi, creator of the Gran Turismo videogame series
- Mara Yamauchi, British long-distance runner
- Wakako Yamauchi, American writer
Other uses:
- Yamauchi, Saga is a former town of Kishima District, Saga Prefecture, Japan