Placide Cappeau (25 October 1808 – 8 August 1877) was a French poet and the author of the poem "Minuit, chrétiens" (1847), set to music by Adolphe Adam and known in English as "O Holy Night" or "Cantique de Noël".

He was expected to follow his father in the family business (vinification and cooperage), but after an accident, he turned to the life of an academic.

With the financial support of Brignon's father, who supplied half the tuition, Cappeau attended a town school and then the Collège Royal d'Avignon.

He was a friend of some of the great writers of the Félibrige, including Frédéric Mistral, Joseph Roumanille, and Alphonse Daudet.

Late in life he apostatized and adopted views as a non-Christian and freethinker that were at odds with his fame as the author of a Christmas text.