Keio (disambiguation)

Keio may refer to:


 * Keiō (慶応), a Japanese era name
 * Keio University (慶應義塾大学), a Tokyo University
 * Keio Corporation (京王電鉄), a Tokyo-based transportation company
 * See under 'Keio...' in Category:Electric multiple units of Japan
 * Keio Flying Squadron series or Keio Yūgekitai, the name of a video game series released on the Sega Mega CD\Sega CD, Sega Saturn, and Sony PlayStation consoles