The Commonwealth Building is a 14-story, 194 ft (59 m) commercial office tower in Portland, Oregon, United States.

Located at 421 SW 6th Avenue between Washington and Harvey Milk Streets, it was designed by architect Pietro Belluschi and built between 1944 and 1948.

The building, which was built as the headquarters in Portland of the Equitable Savings and Loan Association, was originally intended to be 12 stories high but was later expanded to 14.

It was the first tower to be sheathed in aluminum, the first to use double-glazed window panels, and was the first to be completely sealed and fully air-conditioned.

[12] Designed by noted Oregon architect Pietro Belluschi, the 207,864-square-foot (19,311.2 m2) tower is of the International Style.