The Custom House Tower is a skyscraper in McKinley Square, in the Financial District neighborhood of Boston, Massachusetts, in the United States. Construction began in the mid 19th century; the tower was added in the 1910s. Standing at 496 feet (151 m) tall, the tower is currently Boston's 17th-tallest building.

The site was purchased on September 13, 1837. Construction of a custom house was authorized by U.S. President Andrew Jackson. When it was completed in 1849, it cost about $1,076,000, in contemporary U.S. currency, including the site, foundations, etc.

Ammi Burnham Young entered an 1837 competition to design the Boston Custom House, and won with his neoclassical design. This building was a cruciform (cross-shaped) Greek Revival structure, combining a Greek Doric portico with a Roman dome, resembled a four-faced Greek temple topped with a dome. It had 36 fluted Doric columns, each carved from a single piece of granite from Quincy, Massachusetts; each weighed 42 tons (37 metric tons) and cost about $5,200. Only half these actually support the structure; the others are free-standing. They are 5 feet (1.5 m) and 4 inches (162 cm) in diameter and 32 feet (9.7 m) high. Inside, the rotunda was capped with a skylight dome.

The entire structure sits on filled land and is supported by 3,000 wooden piles driven through fill to bedrock. Before land reclamation was done in the mid 1800s, Boston's waterfront extended right to this building. Ships moored at Long Wharf almost touched the eastern face of the building. The Custom House was built at the end of the City docks, to facilitate inspection and registration of cargo. The federal government used the building to collect maritime duties in the age of Boston clipper ships.

The building itself is now a hotel.