Koopmans is a Dutch occupational surname meaning "merchant's".[1] Notable people with the surname include:
- Aart Koopmans (1946–2007), Dutch businessman
- Ger Koopmans (born 1962), Dutch CDA politician
- Leo Koopmans (born 1953), Dutch ice hockey player
- Luuk Koopmans (born 1993), Dutch football goalkeeper
- Marion Koopmans (born 1956), Dutch virologist
- Rachel Koopmans, Canadian historian
- Rudy Koopmans (born 1948), Dutch boxer
- Ruud Koopmans (born 1961), Dutch sociologist
- Thijmen Koopmans (1929–2015), Dutch judge
- Tini Koopmans (1912–1981), Dutch high jumper, discus thrower and shot putter
- Tjalling Koopmans (1910–1985), Dutch American mathematician, physicist and economist and Nobel Laureate
- Koopmans' theorem, a quantum chemistry theorem published by Tjalling Koopmans