Koop is a surname. Notable people with the surname include:
- Aire Koop (born 1957), Estonian actress
- Arnold Koop (1922–1988), Estonian historian, university rector
- Bill Koop (1906–1950), Australian rules footballer
- Doug Koop (born 1960), Australian rules footballer
- C. Everett Koop (1916–2013), Surgeon General of the United States from 1982 to 1989
- Wanda Koop (born 1951), Canadian painter