Millett Opera House, Opera house in downtown Austin, United States.

The Millett Opera House at 110 East Ninth Street is a three-story building of 24-inch limestone walls, designed by Frederick Ruffini and completed in 1878. Its original 800 removable seats and the largest enclosed space in Texas are gone; part of the hand-painted ceiling remains in a meeting room.

Local lumber seller Charles Millett built the opera house in 1878 on one of his lots, and architect Frederick Ruffini designed it. It was one of the largest performance spaces in Texas, with 800 removable seats and 24-inch limestone walls. The Austin Public Free Schools bought it in 1940; after a 1950s demolition threat, it housed a printing company until 1979, when the Austin Club took a long-term lease and later bought it.

Since 1979 the building has housed the Austin Club, a private social club that owns it today. The club renovated the interior into three floors, yet a section of the original hand-painted ceiling remains in one meeting room. The name recalls Charles Millett, the lumber dealer who built it.

The building at 110 East Ninth Street is a private social club, the Austin Club, so visits are not open to the general public; access is for members and their guests. The interior was divided into three stories, so the original performance space and its 800 removable seats no longer exist. A portion of the hand-painted ceiling remains in one meeting room.

The building's 24-inch limestone walls made it the largest enclosed space in Texas when it opened in 1878. Since 1979 it has been the home of the Austin Club, a private social club that owns the structure and divided it into three floors, removing the auditorium.