Ronald Victor Thomas (7 August 1888 – 30 December 1936) was an Australian tennis player. He competed at the 1920 Summer Olympics. Thomas won two doubles titles at the Australasian Championships (now the Australian Open), in 1919 and 1920, and one doubles title at the 1919 Wimbledon Championships. Thomas also finished as runner-up in men's singles at the 1920 Australasian Championships. In the semi finals he beat Horace Rice by serving well and coming to the net at every opportunity, but he was pushed to five sets by the baseliner Rice before winning. The final between Thomas and Pat O'Hara Wood was played in a strong wind and O'Hara Wood won in five sets.

Grand Slam finals

Singles: 1 runner-up

Doubles: 3 titles