Tatiana Dornbusch (née Kostiuk, born 21 November 1982) is a Ukraine-born French chess player who received the FIDE title of Woman Grandmaster (WGM) in 2006.
Born in Chernigov, Ukraine, Tatiana studied management in hotel, resort and tourism at the National Municipal Academy in Kharkiv, where she gained a master's degree in 2006.
Following her fourth place in the under 18 European Championship of 1999, she obtained the FIDE title Woman International Master of chess.
In 2006, Kostiuk won the Condom tournament in France and was awarded the FIDE Woman Grandmaster (WGM) title.
Her Elo Fide rating in May 2013 is 2321 points, placing her at ninth rank of women chess players of Ukraine.