The Mills Building and Tower is a two-building complex following the Chicago school with Romanesque design elements in the Financial District of San Francisco, California.

The structures were declared San Francisco Designated Landmark #76,[6] and were listed on the National Register of Historic Places in 1974.

[8] Named for early San Francisco financial tycoon, Darius Ogden Mills, it is regarded as the city's second skyscraper, after the Chronicle Building (1890).

[9] Completed in 1932 at 220 Bush Street, Mills Tower is a 22-story, 92 m (302 ft) annex designed by George W. Kelham and Lewis Parsons Hobart.

The Mills Building is home to several major financial firms, including SeatMe, Pocket Gems, New York Stock Exchange, and Newedge.