Judith Ungemach ( Zeidler, born 11 May 1968) is a German-Australian world champion rower and Olympic gold and bronze medalist.
Zeidler was born in Beeskow, Brandenburg. She started rowing at the age of thirteen at the East German best rowing club Dynamo Berlin (later Sport Club Berlin).
After three World Junior titles, Zeidler won gold in the women's eight at the 1988 Summer Olympics. A year later she won the world titles in Bled (Slovenia) in the coxless pair. At the 1992 Summer Olympics she won bronze in the women's eight with the unified German eight.
Zeidler lives with her husband, Matthias Ungemach, and two sons and one daughter on Sydney's Northern Beaches.