Three Decembers is a chamber opera in two acts by Jake Heggie to a libretto by Gene Scheer which is based on the unpublished play Some Christmas Letters by Terrence McNally. Created with a role for Frederica von Stade, the work premiered on 29 February 2008 at the Houston Grand Opera (HGO). It commissioned the work in association with the San Francisco Opera and Cal Performances.

The opera was first presented under the working title Last Acts at the world premiere by the Houston Grand Opera. The premiere production was directed by Leonard Foglia with lighting designed by Brian Nason and costumes by Cesar Galindo. The ten-instrument chamber orchestra included two pianos played Heggie himself and Patrick Summers, who also conducted the performance.