| Acronym | Definition |
|---|
| ACTO➣Advocacy Centre for Tenants Ontario (Toronto, Ontario, Canada) |
| ACTO➣Action Officer |
| ACTO➣Association for Counselling and Therapy Online (website; est. 2006) |
| ACTO➣Alliance of Concerned Transport Organizations (Philippines) |
| ACTO➣Amazonian Cooperation Treaty Organization |
| ACTO➣Army Communicative Technology Office |
| ACTO➣Association of Charter Train Operators (UK) |