Ekaterina Zavyalova, former married name Poistogova (born 1 March 1991) is a Russian athlete, who specializes in the 800 metres.
She is best known for initially winning the bronze medal in the 800 meters at the 2012 London Olympics, but in 2015, her bronze was upgraded to silver after countrywoman Mariya Savinova's lifetime ban from competition due to doping, which had annulled all Savinova's results backdating to July 2010 and stripped Savinova's 2012 Olympic gold medal.