Family name Guillau (Guillau 
) , throughout the world, is a very rare surname. The surname Guillau is characteristic of France, where it is a rare surname, Germany, where it is an extremely rare surname, and the United Kingdom. Not in comparison with a country's population, it most frequently occurs in France, Germany, and the United States. More prevalently, Guillau is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Guillau | United Kingdom, Democratic Republic of the Congo, France, United States, Germany |