Koishikawa may refer to:
Places
- Koishikawa, locality within Bunkyo, Tokyo.
People
- Masahiro Koishikawa, noted Japanese astronomer.
Astronomy
- 6097 Koishikawa, Asteroid named after the astronomer
Fictional characters
- Miki Koishikawa, Marmalade Boy character.
- Jin Koishikawa, Marmalade Boy character.
- Chiyako Koishikawa, Marmalade Boy character.