Kvasov or Kvassov (feminine: Kvasova or Kvassova) is a Russian-language surname.
People with the surname include:
Andrey Kvasov (c. 1720 – c. 1770), a notable Baroque architect who worked in Russia and Ukraine. Andrey Kvassov (b. 1976), a Kazakh swimmer. Sergei Kvasov (b. 1983), a Russian professional football player. Yaroslav Kvasov, Ukrainian footballer.