Josiah Burr Plumb (25 March 1816 – 12 March 1888) was an American-born Canadian businessman and parliamentarian. Born in East Haven, Connecticut, Plumb immigrated to Canada in 1865 and settled near Niagara Falls, Ontario. Soon thereafter he became active in the Conservative Party of Canada. He was elected three times as a Member of Parliament for Niagara in the Canadian House of Commons. He was first elected in the Canadian federal election of 1874, but this result was voided, although he successfully defended the seat in a by-election held on 22 December 1874. Although defeated in the 1878 election, he regained his seat in a contested election in 1879. Following a defeat in 1882 election, he was appointed to the Canadian Senate on 8 February 1883 on the recommendation of Sir John A. Macdonald. He served as Speaker of the Senate from 4 April 1887 – 12 March 1888, and thereafter remained in the senate until his death.