Fortuna Publica is an aspect of the Roman Goddess of Luck, Fate, and Chance, Fortuna. As Fortuna Publica She ensures the luck of the populice or state, and is a complimentary idea to Fortuna Privata, the Luck of the Individual.
Fortuna Publica was honored with temples on the Quirinal Hill in Rome in the neighborhood named for them tres Fortunae, "the Three Fortunas". At least two of those three temples were to Fortuna Publica; one was to Fortuna Primigenia, whose full title in Rome was Fortuna Publicae Populi Romani, "the Luck of the Roman People"; another was to Fortuna Publica Citerior (citerior meaning "nearer", probably because it was closer to the center of the city); there is not much known of the third temple to Fortuna. Some identify it as again belonging to Fortuna Primigenia, but it's possible that it too was dedicated to Fortuna Publica. The first temple had as its festival date the 25th of May, and the one to Fortuna Publica Citerior the 5th of April.
Fortuna Publica was sometimes known as Fortuna Populi Romani, the "Luck of the Roman People"; under this name She had an altar way up on Hadrian's Wall, at the fort of Vindolana, at the modern Chesterholm in Northumberland, England.