One Montgomery Tower, Postmodernist skyscraper in Financial District, San Francisco, United States.

One Montgomery Tower is a 500-foot (150-meter), 38-story office skyscraper at the northeast corner of Post and Kearny Streets, part of the Post Montgomery Center complex. Its structural steel columns are clad in red granite and square tempered glass windows with aluminum frames, with small squares marking the intersections of each block of four windows; the first two floors use black granite and steel. The main entrance is at 120 Kearny Street.

The tower was completed in 1982 as part of the Post Montgomery Center complex, alongside the Crocker Galleria mall. Its construction required demolishing the top ten floors of the adjacent Crocker Bank building at 1 Montgomery Street; the shortened building's new roof became a privately owned public open space. The tower was formerly known as Pacific Telesis Tower.

The tower's name comes from its Post Montgomery Center complex, though its main entrance is at 120 Kearny Street. Its ground floor holds one of the first cashierless Amazon Go stores, opened in January 2019, and a consulate general of the Netherlands occupies space in the building. The Wikimedia Foundation was headquartered on the sixteenth floor from 2017 to 2024.

The main entrance is at 120 Kearny Street, not on Montgomery Street, and the tower links directly to the Crocker Galleria mall. The rooftop of the adjacent former Crocker Bank building at 1 Montgomery Street is a privately owned public open space. The ground floor holds a cashierless Amazon Go store.

The tower's main entrance is at 120 Kearny Street, not on Montgomery Street, despite the building's name. From 2017 to 2024 the Wikimedia Foundation had its headquarters on the sixteenth floor. A consulate general of the Netherlands and the San Francisco office of Shook, Hardy & Bacon are also tenants.