Originally called the Church of the Messiah, The Unitarian Church of Montpelier has been a Unitarian Church since it was built in the mid 1800s.

Exterior modifications to the church include changes to the steeple and additions to the west end of the building. The tall spire of the steeple is said to have first soared to 175 feet, but by 1889 was reduced to its existing 100-foot height. Around 1900 the west end of the church was extended so that the organ and choir would be at the front of the sanctuary, where both would be more visible and audible. In the early 1980s a new, two-story west end addition was built to accommodate classrooms and offices. In 2000, steeple restoration was completed.