Marija Šestak (Serbian Cyrillic: ?????? ??????; born Martinovic, ?????????? on 17 April 1979 in Kragujevac, SR Serbia, Yugoslavia) is a Serbian-born Slovenian triple jumper.
She is married to Slovenian 400 metres runner Matija Šestak.
She was granted Slovenian citizenship on 13 July 2006.
Her personal best jump is 15.08 metres, achieved on 13 February 2008 in Athens.
This is the current national record for Slovenia, beating the seven-year-old record of Anja Valant.