| Z | Unix file Compressed |
| Z3 | Game module (Infocom) |
| ZAP | Compressed file (FileWrangler) |
| ZAP | Software installation settings file (Microsoft Windows) |
| ZDG | Compressed text document (Zview) |
| ZER | Data file (Zerberus) |
| ZGM | Graphics file (ZenoGraphics) |
| ZIP | Zip file Compressed archive |
| ZLT | ZoneAlarm Mailsafe Renamed .URL File (Zone Labs) |
| ZOM | Compressed Amiga archive (ZOOM) |
| ZOO | An early compressed file format |
| ZVD | Voice file (Zyxel Z-Fax) |
