1900 U.S. National Championships – Men's singles

Two-time defending champion Malcolm Whitman defeated William Larned in the challenge round, 6–4, 1–6, 6–2, 6–2 to win the men's singles tennis title at the 1900 U.S. National Championships. The event was held at the Newport Casino in Newport, R.I., United States.

Larned had defeated George Wrenn in the All Comers' Final.