Josiah Williams "Si" Pearce (January 18, 1850 – May 25, 1938) was a merchant and politician in Ontario, Canada.

[1][2] The son of Peter Pearce and Almira Edmonds, he was born in Norwood, Canada West, and was educated there.

Pearce began working as a clerk in a general store there, later moving to Marmora, where he opened his own business.

Pearce built the first retail mall in Marmora which included a bakery, a livery store and the town newspaper office.

[2] Pearce was married three times: first to Bessie Bramley in 1877, then to Julia C. Houston in 1891[1] and finally to Mary.