OXI, or Ohi Day, is a holiday in Greece on 28 October.
OXI or Oxi may also refer to:
- Cocaine paste, a crude extract of the coca leaf
- Karakoçan, a town of Elazığ Province in the Eastern Anatolia region of Turkey
- Starke County Airport, the FAA LID code OXI
- Roxicodone, a trade name for opioid oxycodone