William Clyde Caldwell (May 14, 1843 – January 7, 1905) was an Ontario businessman and political figure.

He represented Lanark North in the Legislative Assembly of Ontario as a Liberal member four times from 1872 to 1875, 1879 to 1886, 1888 to 1894 and 1898 to 1905.

Around 1872, he adopted the middle name Clyde, after the Clyde River in Lanark County where the family held timber limits, to distinguish himself from several other William Caldwells in the province.

He became part-owner of a grist mill in Carleton Place and built a sawmill in Almonte.

He was elected in an 1872 by-election to represent Lanark North in the Ontario legislature.