William J. Campbell (died 1950) was a politician in Manitoba, Canada. He served in the Legislative Assembly of Manitoba from 1945 to 1949, as a member of the Progressive Conservative Party.
Campbell lived in Teulon, Manitoba. He was elected to the provincial legislature in the 1945 election, defeating Liberal-Progressive incumbent Mungo Lewis by 297 votes in the Rockwood constituency.
The Liberal-Progressives and Progressive Conservatives were partners in a coalition government during this period, and Campbell sat as a government backbencher during his time in the legislature. He did not run for re-election in 1949, and died the following year.