William Mair may refer to:
William Mair (South Australian politician) (died 1897), member of the South Australian House of Assembly Bill Mair (1900–1964), Australian politician, member of the Victorian Legislative Council William Mair (chemist) (1868–1948), Scottish pharmacist and manufacturing chemist William Mair (moderator) (1830–1920), Scottish minister William Crosbie Mair (died 1831), Scottish physician William Gilbert Mair (1832–1912), soldier, resident magistrate, and judge in New Zealand