OSE may be:

• An acronym standing for Operating System Embedded, a real-time operating system created by the Swedish firm ENEA.
• An abbreviation of OPENSTEP Enterprise, NeXT's offering of the OpenStep platform for the Microsoft Windows operating system.
• An abbreviation of Organismós Sidirodrómon Elládos (Hellenic Railways Organisation), the state railway of Greece.
• An abbreviation of Osaka Securities Exchange
• An abbreviation of Oslo Stock Exchange