Michel-Guillaume Baby (September 15, 1834 – March 16, 1911) was a businessman and political figure in Quebec.

He was born in Saint-Philippe-de-La Prairie, Lower Canada, the son of Charles François Xavier Baby and Clothilde Pinsonaut.

He was first elected to the legislative assembly for the Province of Canada in an 1857 by-election held after Joseph-Charles Taché resigned his seat.

Baby was first elected to the Quebec assembly in an 1874 by-election held after Pierre-Alexis Tremblay resigned his seat.

Baby died there at the age of 76 and was buried in Quebec City.