Rugby union at the 1900 Summer Olympics was played in Paris. Rugby union matches at the 1900 Summer Olympics were held on 14 October and 28 October. Forty-seven athletes competed, most from three nations and including a Haitian and a French-born American.

Rugby union football, commonly known simply as rugby union or more often just rugby, is a close-contact team sport that originated at Rugby School in England in the first half of the 19th century. Rugby is simply based on running with the ball in hand. In its most common form, a game is played between two teams of 15 players each, using an oval-shaped ball on a rectangular field called a pitch. The field has H-shaped goalposts at both ends.