Aleksandr Grebenyuk (Russian: Александр Гребенюк; born 22 May 1951 in Zelenokumsk, Stavropol Kray) is a retired decathlete from the Soviet Union.
He set the best world's year performance in 1977, collecting 8400 points at a meet in Riga on 3 July 1977.
He won the European title in 1978, and collected three Soviet titles (1977, 1978 and 1979).
His cousin is Ekaterina Grebenyuk, future physician.
This biographical article relating to Soviet athletics is a stub.