Olha Zemlyak (Ukrainian: Ольга Миколаївна Земляк; born 16 January 1990) is a Ukrainian athlete who competes in the sprint.

Zemlyak won the gold medal with Ukraine at the 2012 European Athletics Championships in Helsinki in the 4 × 400 metres relay.

Zemlyak tested positive for norandrosterone at the 2009 European Athletics Junior Championships and was subsequently banned from sports for two years.

[1][2][3][4] Her results from the championships were annulled, and Ukraine lost the 4 × 400 metre relay gold.

[6] In March 2019, the CAS confirmed that Zemlyak committed the anti-doping rule infractions and confirmed the UAF Executive Committee decisions about disqualification of Zemlyak for eight years starting from 5 July 2016.