| Rank | Abbreviation | Meaning |
|---|
| ***** | OASA | Office of the Assistant Secretary of the Army
| |
| ***** | OASA | of Alcoholism and Substance Abuse
| |
| **** | OASA | Ontario Amateur Softball Association
| |
| **** | OASA | Ottawa Area Superintendents' Association
| |
| *** | OASA | Ontario Amputee Sports Association
| |
| *** | OASA | Oregon Adult Soccer Association
| |
| *** | OASA | Observatório Astronómico de Santana, Açores
| |
| *** | OASA | Oceanic and Atmospheric Administration
| |
| *** | OASA | Oregon Ambulatory Surgery Association
| |
| *** | OASA | Organismos Astikon Siginonion Athinon
| |
| ** | OASA | Office of Alcohol and Substance Abuse
| |
| ** | OASA | Office of the Assistant Secretary for Aging
| |
| ** | OASA | Observer's Assessment of Sedation and Anesthesia
| |
| ** | OASA | Office of the Assistant Secretary for Administration
| |
| ** | OASA | Office of Academic and Student Affairs
| |
| ** | OASA | Oklahoma Amateur Softball Association
| |
| * | OASA | Organization of American States
| |
| * | OASA | Office Administration Student Association
| |
| * | OASA | Older Adult Services Act
| |
| * | OASA | OpenOffice.org Association for South Africa
| |
| * | OASA | Oklahoma Association of School Administrators
| |
| * | OASA | Orienteering Association of South Australia
| |
| * | OASA | Olympic and Amateur Sports Act
| |
| * | OASA | Oxford Area Sewer Authority
| |
| * | OASA | Oregon Abuse Survivors and Advocates
| |