Dagmar Hase (born 22 December 1969 in Quedlinburg, Saxony-Anhalt, East Germany) is a retired German swimmer.

Her defeat of American swimmer Janet Evans in the 400 metre freestyle at the 1992 Barcelona Olympics was Evans's only loss in a 400 or 800 metre freestyle between 1986 and 1994.

At the World Championships in 1994 she qualified for the 200 metre freestyle as the eight best swimmer, but her teammate Franziska van Almsick swam only the ninth best qualification time.

Therefore Hase abandoned her start place and offered it to van Almsick, who then won the gold medal in the final bettering the world record.

This article about a swimming Olympic medalist for Germany is a stub.