Dempster can refer to:
- People
- Arthur Jeffrey Dempster, U.S. physicist who discovered the 235U uranium isotope
- Arthur P. Dempster, U.S. mathematician who, with Glenn Shafer, created the Dempster-Shafer theory of evidence
- Barry Dempster, Canadian writer
- Carol Dempster, U.S. actress
- Charlotte Louisa Hawkins Dempster, British writer and folklorist
- Dallas Dempster, Australian businessman
- Eric Dempster, New Zealand cricketer
- George Dempster (lawyer), Scottish lawyer and MP
- George Roby Dempster, U.S. businessman and politician, founder of Dempster Brothers, Inc.
- Graham Dempster, Australian rules football player
- Hugh Dempster, British actor
- Jocky Dempster, Scottish footballer
- John Dempster (Medal of Honor), U.S. Civil War sailor
- John Dempster (footballer), English footballer
- Nigel Dempster, British journalist, author and broadcaster
- Quentin Dempster, Australian journalist
- Roland T. Dempster, Liberian writer
- Ryan Dempster, Canadian-born U.S. baseball player
- Sean Dempster, Australian rules football player
- Stephen Dempster, Canadian religious scholar
- Stewie Dempster, New Zealand cricketer
- Stuart Dempster, U.S. musician
- Thomas Dempster, Scottish scholar and historian
- Walter Dempster, Philippine drag queen and World War II sex slave
- Other
- Dempster Land District, Western Australia
- Dempster Highway, a Canadian roadway, in the Yukon and Northwest Territories
- Dempster Street, a major east-west artery north of Chicago, Illinois, part of which is part of U.S. Route 14
- Dempster (CTA Purple Line station), a Chicago Transit Authority rapid transit station in Evanston, Illinois
- Dempster-Skokie (CTA station), a Chicago Transit Authority rapid transit station in Skokie, Illinois
- Dempster Brothers, Inc., a Tennessee industrial firm
- Dempster Dumpmaster, a garbage-handling vehicle manufactured by the company
- Dempster Dumpster, a waste receptacle manufactured by the company
- Dempster's brand bread, a product of Maple Leaf Foods