Guillaum Seignac (1870–1924) was a French academic painter.
He was born in Rennes, France, in 1870, and died in 1924. He started training at the Académie Julian in Paris, where he spent 1889 through 1895. He had a lot of teachers there, including Gabriel Ferrier, and Tony Robert-Fluery. Tony Robert Fluery was a noted history and genre artist. Gabriel Farrel, on the other hand, had been an awarded Prix de Rome. He had another one named William Bouguereau.
In addition to his training in the academic style, much of Seignac's work displayed classical themes and style, for example, is use of diaphanous drapery covering a woman's body is reminiscent of classical style, in particular the sculptor Phidias. In 1897, Guillaume Seignac regularly exhibited at the Salon and won several honors, including in 1900 honorable mention and in 1903 a Third Class medal.