Flavien-Guillaume Bouthillier (March 2, 1844 – July 20, 1907) was a lawyer and political figure in Quebec.
He was born in Saint-Césaire, Canada East, the son of Flavien Bouthillier and Marguerite-Henriette Blumhart, and was educated at the Collège de Sainte-Marie-de-Monnoir, the Collège de Saint-Hyacinthe, the Université Laval and Victoria University in Cobourg, Ontario.
He articled in law with Antoine-Aimé Dorion, was admitted to the Quebec bar in 1871 and set up practice in Montreal, first on his own and later with Philippe-Honoré Roy.
Bouthillier was a promoter of the St. Lawrence, Lower Laurentian & Saguenay Railroad.
He was defeated by Victor Robert when he first ran for a seat in the Quebec assembly in 1875.