The Custom House Tower is a skyscraper in McKinley Square, in the Financial District neighborhood of Boston, Massachusetts. The original building was constructed in 1837–47 and was designed by Ammi Burnham Young in the Greek Revival style. The tower was designed by Peabody and Stearns and was added in 1913–15. The building is part of the Custom House District, which was added to the National Register of Historic Places in 1973.

Ammi Burnham Young was a 19th-century American architect whose commissions transitioned from the Greek Revival to the Neo-Renaissance styles. His design of the second Vermont State House brought him fame and success, which eventually led him to become the first Supervising Architect of the U.S. Treasury Department. As federal architect, he was responsible for creating across the United States numerous custom houses, post offices, courthouses and hospitals, many of which are today on the National Register. His traditional architectural forms lent a sense of grandeur and permanence to the new country's institutions and communities. Young pioneered the use of iron in construction.