Charles-Jean Grandmougin (17 January 1850 – 28 April 1930) was a French poet and playwright. He lived in Paris. Two of his poems appeared in the third and final volume of Le Parnasse contemporain (1876). His poetry has been set as songs by composers including Fauré, Chaminade, Pierné and Bizet. He was more well known as a librettist and translator for operas and oratorios. He wrote the libretto for César Franck's opera Hulda, set in 11th-century Norway, and based on the play Lame Hulda (1858) by Norwegian writer Bjørnstjerne Bjørnson. He also wrote the libretto for La Vierge, an oratorio by Jules Massenet.