The 1900 Pittsburgh Pirates season was the 19th season of the Pittsburgh Pirates franchise. The Pirates finished second in the National League with a record of 79–60.

The 1900 Brooklyn Superbas captured their second consecutive National League championship by four and a half games. The Baltimore Orioles, which had been owned by the same group, folded after the 1899 season when such arrangements were outlawed, and a number of the Orioles' players, including star pitcher Joe McGinnity, were reassigned to the Superbas.