William Blair
William Blair may refer to:
- William Blair (American politician), member of the Wisconsin State Senate
- William Blair (Australian footballer), Australian footballer and umpire
- William Blair (Ayrshire MP), member of parliament for Ayrshire 1829–1832
- William Blair (judge), British judge and KC; elder brother of U.K. prime minister Tony Blair
- William Blair (Nova Scotia politician), farmer and political figure in Nova Scotia, Canada
- William Blair (Royal Navy officer), Scottish sailor and captain in the Royal Navy
- William Blair (Scottish footballer), Scottish international footballer
- William Blair (surgeon), British surgeon and writer on ciphers
- William D. Blair, Jr, reporter, State Department spokesman, president of The Nature Conservancy
- William Gourlay Blair, Canadian politician and physician
- William H. Blair, American Civil War Union Brevet Brigadier General
- William John Blair, Canadian engineer and politician
- William M. Blair, investment banker from Chicago
- William McCormick Blair Jr., U.S. ambassador; son of William M. Blair
- William Newsham Blair, New Zealand engineer and surveyor
- William R. Blair, American scientist and U.S. Army officer
- William R.N. Blair, Canadian psychologist and academic administrator
- William W. Blair, leader in the Reorganized Church of Jesus Christ of Latter Day Saints
- William Blair Tennent, New Zealand politician and cabinet minister
- Willie Blair, American baseball player
Companies
- William Blair & Company, a Chicago-based investment banking firm founded by William M. Blair