- 4 Star Hotel
- 44 Nigerian Army Reference Hospital
- 68 Nigerian Army Reference Hospital
- 7Eleven Consultancy Services
- A 24/7 Online Food Delivery Services Company
- A.G Leventis Nigeria Limited
- Abdul Latif Jameel Poverty Action Lab (J-PAL)
- Abodes Lagos
- Absa Group
- Abt Associates
- Accion International
- ACDI/VOCA
- Achievers University
- Achieving Health Nigeria Initiative (AHNi)
- ACI Worldwide
- Acronis International GmbH
- Acumen West Africa
- Ad Dynamo International
- Adeeva Capital Limited
- Adkan Construction Company Limited
- Afconrecruit Limited
- Affilbase
- African Development Bank Group (AfDB)
- African Natural Resources & Mines Limited (ANRML)
- African Regional Institute for Geospatial Information Science and Technology (AFRIGIST)