Across the world, Mabiala-Ntoumou-Sy (Mabiala-Ntoumou-Sy 
) is an extremely rare unknown gender first name. Much more frequently, Mabiala-Ntoumou-Sy is the last name as well as the forename. Parts of the name also exists independently as a last name Mabiala, a last name Ntoumou, and a last name Sy.
| VARIANT | COUNTRY |
|---|---|
| Mabiala-Ntoumou-Sy | Democratic Republic of the Congo |