She married the broadcaster Harri Gwynn on 1 January 1942. They remained married until his death in 1985. They had a son, Iolo ap Gwynn, who went on to become a lecturer in biology at the University of Wales and joined Plaid Cymru. Gwynn died suddenly of a heart attack at her home in Tal-y-bont, Ceredigion, on 26 January 2007; she had rheumatism that kept her housebound. She was buried alongside her husband close to Llanrug in accordance with her wishes.