William Dennis (disambiguation)
William Dennis was an Independent Conservative member of the Senate of Canada.
- William Henry Dennis, his nephew and Canadian Conservative senator from 1912 to 1920
- Billy Dennis (English footballer), English footballer
- Willie Dennis, American jazz musician
- Willie D, rapper
- Bill Dennis, NASCAR driver
- William Lockyer Dennis, English-born American politician
- William M. Dennis, American businessman and politician
- William S. Dennis, American captain of the Vanitie yacht in the America's Cup trials
- Will Dennis, English footballer