Katherine FitzGerald, Countess of Desmond (c. 1504 – 1604) was a noblewoman of the Anglo-Norman FitzGerald dynasty in Ireland. English writers of the Tudor period, including Sir Walter Raleigh, helped popularise "the old Countess of Desmond" as a nickname for her, due to her longevity. One estimate placed her age at death in excess of 120 years. Another ranged as high as 140. Most likely she lived to about 100.