First Market Tower, Office skyscraper in Financial District, San Francisco, United States.

First Market Tower stands at 525 Market Street, on the southwest corner of First and Market Streets in San Francisco's Financial District. The 161 m (528 ft) tower has 39 floors and was designed by John Carl Warnecke and Associates. When completed it was the city's second largest office building by square footage, after 555 California Street.

Designed by John Carl Warnecke and Associates, the tower was completed in 1972 or 1973, depending on the source; the English Wikipedia gives 1973, the Czech article 1972. At 161 m and 39 floors, it was the second-largest office building in San Francisco by square footage after 555 California Street when completed. In 2020 a 49% stake was sold to a Deutsche Bank subsidiary for $682 million.

The tower's name comes from its corner at First and Market Streets; it was long called First Market Tower before its address, 525 Market Street, became the common name. Amazon occupies about 40% of the floor area, housing its Web Services and Music divisions, and Sephora has its North America headquarters here.

The building is centrally located on Market Street and is easily accessible by public transportation. As a private office building, visitor access may be limited to common areas and lobbies.

The building is among several San Francisco high-rises that required structural reinforcement due to welding techniques used during its original construction. City geological surveys identified this issue and led to improvements in future building projects.