Thelma Bessie Forbes (September 26, 1910 – January 5, 2012) was a politician in Manitoba, Canada. She was a Progressive Conservative member of the Legislative Assembly of Manitoba from 1959 to 1969, and served as a cabinet minister in the governments of Dufferin Roblin and Walter Weir. Forbes was the third woman ever elected to serve in the Manitoba legislature, the first woman to serve as speaker for the legislature and the first to serve in cabinet.