OSCI can refer to:

• Open SystemC Initiative, now Accellera
• Oshkosh Correctional Institution

The Osci (also called Opici, Opsci, Obsci, Opicans, ), were an Italic people of Campania and Latium adiectum during Roman times. They spoke the Oscan language, also spoken by the Samnites of Southern Italy. Although the language of the Samnites was called Oscan, the Samnites were never called Osci, or the Osci Samnites.