Surname ガイ (Guy 
, Gaj 
, Gai 
) , all around the world, is a widespread family name. The surname ガイ is characteristic of Israel, where it is a common surname, Monaco, and Saint Vincent and the Grenadines (explore the name in all countries). In absolute terms, it most frequently occurs in China, the United States, and France. More frequently, ガイ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Guy | United States, Cameroon, China, Democratic Republic of the Congo, France |
| Gaj | United Kingdom, Poland, United States, India, France |
| Gai | United States, Israel, China, Democratic Republic of the Congo, France |
| ガイ | Japan |