Kooi, Kooij or Kooy is a Dutch surname. Translated as "cage", the name often referred to a pen or duck decoy, and originated with a herder, duck breeder/hunter, or cage maker. The forms Van der Kooi etc. mean "from the pen / duck decoy". In the Netherlands, the archaic spelling Kooij is most common, while it is usually rendered Kooy abroad. Notable people with the surname include:
