3I or 3-I may refer to:

Iniziative Industriali Italiane

• 3I Sky Arrow

• 3i London-based private equity and venture capital company

• 3-I League, see Illinois–Indiana–Iowa League

• 3i Infrastructure, an investment business headquartered in Jersey

• 3i Infotech Limited, an Indian IT company

• ESX Server 3i, a version of VMware ESX

• Comet 3I/ATLAS, the third known interstellar interloper

See also

• I3 (disambiguation)