Nataliya Viktorivna Tobias (Ukrainian: Наталія Вікторівна Тобіас, née Sydorenko (Сидоренко); born 22 November 1980 in Serov, Soviet Union) is a female former middle-distance runner from Ukraine, who specialized in the 1500 metres.

[2] Tobias represented her country at the Olympics twice, including a 1500 m bronze medal at the 2008 Beijing Olympics.

She also competed at the World Championships in Athletics in 2007 and 2011, and was the 1500 m gold medallist at the 2003 Summer Universiade.

[3] During her career, she won Ukrainian national titles in five different events.

[2] Tobias received a two-year ban in 2012 for testing positive for testosterone at the 2011 World Athletics Championships.