Guillaume Gamelin Gaucher (August 16, 1810 – September 16, 1885) was a Quebecois businessman and political figure.
He represented Jacques-Cartier in the 1st Canadian Parliament as a Conservative member.
He was born Jean-Guillaume Gaucher in Sault-Saint-Louis (later (Kahnawake) in 1810 and was educated there.
He became a merchant at Sainte-Geneviève on the Island of Montreal.
Gaucher served as a lieutenant-colonel in the local militia and was also a justice of the peace.