Birgit Koschischek (born 22 May 1987 in Vienna) is an Austrian swimmer, who specialized in sprint freestyle and butterfly events.

[3][4] In 2008, Koschischek reached the semifinals of the freestyle and butterfly (both 100 m) at the European Championships in Eindhoven, Netherlands, with respective times of 56.15 and 59.61.

Having cleared FINA B-cuts in both events, she guaranteed a spot on the Austrian swimming team for the Olympics.

On the first night of the Games, Koschischek won the third heat of the 100 m butterfly, by 0.28 of a second ahead of Hong Kong's Hannah Wilson in an Austrian record of 59.07, but she missed out the semifinals by 0.58-second deficit, as she placed twenty-sixth out of 69 swimmers in the preliminaries.

[9] She also achieved an eighth-place finish, and eventually added her fifth-career Austrian record (2:07.46) in the women's 200 m butterfly at the 2011 European Short Course Swimming Championships in Szczecin, Poland.