Oleksiy Demyanyuk (July 30, 1958 in Baranivka, Ukrainian SSR - April 5, 1999) was a high jumper from the Soviet Union, who set the world's best year performance in 1981 with a leap of 2.33 metres at a meet in Leningrad. He ended up in eleventh place at the 1980 Summer Olympics in Moscow.
His son, Dmytro Dem'yanyuk, is also a high jumper.