Antonín Mrkos (Czech pronunciation: [ˈantoɲiːn ˈmr̩kos]; 27 January 1918 – 29 May 1996) was a Czech astronomer, born in Střemchoví, Czechoslovakia.

Mrkos entered the University in Brno in 1938. His studies were interrupted by the onset of World War II, and in 1945 he became a staff member at the Skalnaté Pleso Observatory in Slovakia. It was from here that he carried out his extremely active cometary programme and became the discoverer of several unusual comets, the most famous of them the bright Comet 1957d.

He was the second Czech in Antarctica and the first Czechoslovak to reach the Southern pole of inaccessibility as a member of the 3rd Soviet Antarctic Expedition (1957–1959). The Czechoslovakian flag was the second flag raised after the flag of the USSR. He returned to Antarctica as the head of the 4 member Czechoslovakian crew in the 7th Soviet Antarctic Expedition (1961 – 1963). He was studying auroras among other things. He was invited for what would have been his third expedition to the Antarctic but couldn't participate because of an almost fatal accident. It's thought someone tried to injure or to kill him by adding a bottle of strongly concentrated detergent among his other bottles of mineral water. Since this accident he could only eat liquid meals for the rest of his life.