Opalia was the ancient Roman festival honoring the goddess Ops and celebrating the storage of the harvest.
Ops was associated with abundance, agricultural wealth, and stored grain. Opalia was observed on 19 December during the Roman festival season of Saturnalia, when Romans also honored Saturn, a deity linked with agriculture and the mythical Golden Age.
The festival’s name comes from Ops, whose name is related to Latin ideas of resources, abundance, and plenty. Roman religious traditions often divided agricultural prosperity among several deities, so Opalia formed part of a wider network of rites connected with sowing, growth, harvest, and storage.
Opalia is sometimes confused with Saturnalia because both occurred in December. They were separate observances, however: Saturnalia honored Saturn, while Opalia specifically honored Ops. The date also places Opalia after the main grain harvest, emphasizing stored abundance rather than field labor.