OSC may refer to:
- Canons Regular of the Order of the Holy Cross
- Odborové sdružení československé, the Czechoslovak Trade Union Association
- Office of Special Counsel (in the United States of America)
- Off-Site Construction, a mode of building
- Ohio Supercomputer Center
- "One Step Closer" (Linkin Park song), a song by American rock band Linkin Park
- Ontario Science Centre, a science museum in Toronto, Canada
- Ontario Securities Commission
- oogonial stem cells
- Open Sound Control, a music-oriented electronic communications protocol used for among computers and multimedia devices
- Open Source Center, a United States government center that provides analysis of open-source intelligence
- openSUSE Command-line tool, a command-line tool used for openSUSE build service
- Operating System Command, character 9D in the Unicode character set, see UTF-EBCDIC
- Orbital Sciences Corporation, a satellite-oriented company
- Order to show cause, a court order to obtain information or proof
- Order of Saint Clare, a Religious Order founded by Clare of Assisi, also known as the Poor Clares, whose members use the post-nominal letters OSC
- Organic solar cell
- Orlando Science Center, a science-education establishment in Florida
- Orson Scott Card, a writer
- Osceola (Amtrak station), Iowa, United States; Amtrak station code OSC
- osCommerce, an e-retailing software package
OSC also serves as an abbreviation for oscillator