Gisela Agnes of Rath (9 October 1669 in Kleinwülknitz, now part of Köthen – 12 March 1740 in Nienburg) was Duchess of Anhalt-Köthen by marriage from 1692.
In 1694, she was created Countess of Nienburg.
From 1704 to 1715, she was regent of Anhalt-Köthen for her underage son.