| OSA | Oakland School for the Arts 
| Others |
| OSA | Object Oriented Systems Analysis
| Others |
| OSA | Object Storage Architecture
| Others |
| OSA | Observability Subspace Algorithm
| Others |
| OSA | Obstructive Sleep Apnea
| Others |
| OSA | Obstructive sleep apneas
| Others |
| OSA | Obstructive Sleep Apnoea
| Others |
| OSA | Obstructuve Sleep Apnea
| Others |
| OSA | Office of Special Affairs
| Others |
| OSA | Office of Student Activities
| Others |
| OSA | Office of Student Affairs
| Others |
| OSA | Office of the Science Advisor
| Others |
| OSA | Office of the Secretary of the Army
| Others |
| OSA | Office of the State Architect
| Others |
| OSA | Office of the State Auditor
| Others |
| OSA | Office Support Assistant
| Others |
| OSA | Office Systems Architecture
| Others |
| OSA | Official Secrets Act
| Others |
| OSA | Officials Secret Act
| Others |
| OSA | Oklahoma Soccer Association
| Others |
| OSA | Olancho San Agustin
| Others |
| OSA | Old School Arcade
| Others |
| OSA | Old Students Association
| Others |
| OSA | Omaha Sports Academy
| Others |
| OSA | Omicsoft Sequence Aligner
| Others |
| OSA | Omnibus Service Authority
| Others |
| OSA | On Shelf Availability
| Others |
| OSA | One Step Ahead
| Others |
| OSA | Online Safety Alliance
| Others |
| OSA | Online Scholarship Application
| Others |
| OSA | Online Services Advisor
| Others |
| OSA | Online Sexual Addiction
| Others |
| OSA | Online Signatory Application
| Others |
| OSA | Online Soccer Academy
| Others |
| OSA | Only Store Administrative
| Others |
| OSA | Ontario Soccer Association
| Others |
| OSA | Ontario Society of Artists
| Others |
| OSA | Open Scripting Architecture
| Others |
| OSA | Open Service Access
| Others |
| OSA | Open Service Architecture
| Others |
| OSA | Open Services Architecture
| Others |
| OSA | Open Simulation Architecture
| Others |
| OSA | Open Society Archive
| Others |
| OSA | Open Society Archives
| Others |
| OSA | Open Solutions Alliance
| Others |
| OSA | Open Source Architecture
| Others |
| OSA | Open Space Agency
| Others |
| OSA | Open Space Alliance
| Others |
| OSA | Open Standard Architecture
| Others |
| OSA | Open Structure Anti
| Others |
| OSA | Open Structure Antiglare
| Others |
| OSA | Open System Architecture
| Others |
| OSA | Open System Authentication
| Others |
| OSA | Open Systems Adapter
| Others |
| OSA | Open Systems Architecture
| Others |
| OSA | Operating System Administrator
| Others |
| OSA | Operational Security Assurance
| Others |
| OSA | Operational Services Agreement
| Others |
| OSA | Operational Support Airlift
| Others |
| OSA | Operational Support Area
| Others |
| OSA | Opportunity Success and Ambition
| Others |
| OSA | Optical Society of America
| Others |
| OSA | Optical Spectrum Access
| Others |
| OSA | Optical Spectrum Analyzer
| Others |
| OSA | Optical Subassembly
| Others |
| OSA | Oracle Sales Analyser
| Others |
| OSA | Orangutans Seem Alert
| Others |
| OSA | Order of Saint Augustine
| Others |
| OSA | Oregon Student Association
| Others |
| OSA | Organic Seed Alliance
| Others |
| OSA | Organization of Staff Analysts
| Others |
| OSA | Orissa Society of America
| Others |
| OSA | Orissa Society of Americas
| Others |
| OSA | Orsini Security Agency
| Others |
| OSA | Osage
| Others |
| OSA | Oshkosh Student Association
| Others |
| OSA | Out of Band Services Architecture
| Others |
| OSA | Out of Station Allowance
| Others |
| OSA | Outdoor Soccer of America
| Others |
| OSA | Output Stuck At
| Others |
| OSA | OutStanding Achievement
| Others |
| OSA | Outstanding Silliman Awardee
| Others |
| OSA | Outstanding Student Award
| Others |
| OSA | Over Sampling
| Others |
| OSA | Over Speed Alarm
| Others |
| OSA | Overhead Squat Area
| Others |
| OSA | Sleep Apnea
| Others |
| OSA | The Office Of Secret Actions
| Others |