| OIS | Conference on Office Information Systems 
| Others |
| OIS | O'Brien Investment Services
| Others |
| OIS | Oahu Information Service
| Others |
| OIS | Oakcrest Intermediate School
| Others |
| OIS | Object Oriented Input System
| Others |
| OIS | Objective Interface Systems
| Others |
| OIS | Odometer Inspection Services
| Others |
| OIS | Office for Information Systems
| Others |
| OIS | Office for International Services
| Others |
| OIS | Office Information System
| Others |
| OIS | Office Installation Services
| Others |
| OIS | Office of Information Services
| Others |
| OIS | Office of Information Systems
| Others |
| OIS | Office of Instructional Services
| Others |
| OIS | Office of International Services
| Others |
| OIS | Office of International Students
| Others |
| OIS | Office of International Studies
| Others |
| OIS | Officer Indoctrination School
| Others |
| OIS | Officer Involved Shooting
| Others |
| OIS | Officer-Involved Shooting
| Others |
| OIS | Oh, I See!
| Others |
| OIS | Ohio Intermodal Services
| Others |
| OIS | OMNI Information Services
| Others |
| OIS | Onboard Information System
| Others |
| OIS | Online Information Service
| Others |
| OIS | Online Information System
| Others |
| OIS | Only In Spain
| Others |
| OIS | Open Innovation Space
| Others |
| OIS | Open Innovation Summit
| Others |
| OIS | Open Interconnected System
| Others |
| OIS | Open Interface Specification
| Others |
| OIS | Operational Information Service
| Others |
| OIS | Operational Information system
| Others |
| OIS | Operational Intercommunication System
| Others |
| OIS | Ophthalmology Innovation Summits
| Others |
| OIS | Optical Image Stabilisation
| Others |
| OIS | Optical Image Stabilization
| Others |
| OIS | Optical Image Stabilizer
| Others |
| OIS | Optical Intrinsic Signal
| Others |
| OIS | Optimal Image Scale
| Others |
| OIS | Orbiter Insertion Stage
| Others |
| OIS | Orbiter Instrumentation System
| Others |
| OIS | Oregon Intervention System
| Others |
| OIS | Organization Information Structure
| Others |
| OIS | Oriental Institute Seminars
| Others |
| OIS | Oriented Input System
| Others |
| OIS | Original Inner Sleeve
| Others |
| OIS | Orinda Intermediate School
| Others |
| OIS | Oslo International School
| Others |
| OIS | Other Interpretations of Sentences
| Others |
| OIS | Outpatient Infusion Systems
| Others |
| OIS | Overhead Information Symbol
| Others |
| OIS | Overnight Index Swap
| Others |
| OIS | Overnight Indexed Swap
| Others |
| OIS | Oxford Intermediate School
| Others |