Nataliya Viktorivna Tobias (, 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. She holds personal bests of 4:01.78 minutes for the 1500 m, 2:02.31 minutes for the 800 metres, and 8:51.32 minutes for the 3000 metres. 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. During her career, she won Ukrainian national titles in five different events. Tobias received a two-year ban in 2012 for testing positive for testosterone at the 2011 World Athletics Championships.

International competitions

National titles

Personal bests