Publilius Optatianus Porfirius was a Latin poet, possibly a native of Africa.
He flourished during the 4th century. Porfirius has been identified with Publilius Optatianus, who was praefectus urbi (in 329 and 333), and is by some authorities included amongst the Christian poets. For some reason he had been banished, but having addressed a panegyric to the Emperor Constantine I, he was allowed to return.
Twenty-eight poems are extant under his name, of which twenty were included in the panegyric. The content of the poetry is rather trivial. However, the form of the works can be regarded as a specimen of perverted ingenuity. Some of them are squares (the number of letters in each line being equal), certain letters being rubricated so as to form a pattern or figure, and at the same time special verses or maxims; others represent various objects (a syrinx, an organ, an altar); others have special peculiarities in each line (number of words or letters) while the eighth poem (the versus anacyclici) may be read backwards without any effect upon sense or metre. A complimentary letter from the emperor and letter of thanks from the author are also extant.