Ati may refer to:
As an acronym, ATI may refer to:
- ATI Technologies Inc., a technology company and a subsidiary of AMD
- ATI - Advisor Turning Independent, a financial advisor who currently works at a brokerage house thinking about starting his or her own brokerage service
- ATI - Aero Trasporti Italiani, a defunct Italian airline
- Acronis True Image, a software product
- Air Transport International, a charter cargo airline
- Allegheny Technologies, a steel company, ATI on the New York Stock Exchange
- Allied Telesis, a telecommunications company, formerly Allied Telesyn
- Auckland Technical Institute, now the Auckland University of Technology
- Ohio State University Agricultural Technical Institute
- Tunisian Internet Agency (Agence tunisienne d'Internet), a Tunisian ISP