Welsby is a surname. It may refer to:
Arthur Welsby (1902–1980), footballer Chris Welsby (born 1948), filmmaker Elton Welsby (born 1951), English television sports presenter John Welsby (1938–2021), Chief Executive of the British Railways Board Thomas Welsby (1858–1941), Queensland businessman, author, politician, and sportsman. William Newland Welsby (d. 1864), legal writer
It might also refer to Welsby, Queensland, a locality on Bribie Island named after Thomas Welsby.