Kostiuk or Kostyuk () is a patronymic surname of Ukrainian origin derived from the personal name "Kosty, Kost", and the Ukrainian diminutive suffix "-uk/yuk". Thus, the surname Kostiuk can be interpreted as "son or descendant of Kosty or Kost". The name Kosty or Kost is a pet form of the male given name Kostiantyn.
Kostyuk may also be a diminutive given name derived from "Kostiantyn", and it may produce patronymic surnames as well: Kostiukovich, Kostiuchenko.
Notable people with the surname include:
Denys Kostyuk (born 1982), Ukrainian bicycle racer Dmytro Kostiuk (born 1993), Ukrainian journalist and politician Eric Kostiuk Williams (born 1990), Canadian cartoonist Ihor Kostyuk (born 1975), Ukrainian footballer Iurii Kostiuk (born 1977), Ukrainian Paralympic biathlete and skier Marta Kostyuk (born 2002), Ukrainian tennis player Mike Kostiuk (1919–2015), American gridiron football player Platon Kostiuk (1924–2010), Ukrainian physiologist Sergey Kostyuk (born 1978), Ukrainian and Kazakhstani footballer Serhiy Kostyuk (born 1986), Ukrainian footballer Tatiana Kostiuk (born 1982), Ukrainian chess player Valeriy Kostyuk (born 1940), Russian physicist Vasyl Kostyuk (born 1989), Ukrainian footballer Volodymyr Kostiuk (2003), Ukrainian gymnast Vladimir Kostyuk (born 1972), Turkmenistani footballer Yevhen Kostyuk (born 2002), Ukrainian footballer
See also