Geraldine Mary Harmsworth (née Maffett; 24 December 1838 – 29 August 1925) was an Irish matriarch.

At a young age, Harmsworth was a talented singer and piano player, who apparently could memorise the operas she heard performed in Dublin.

Harmsworth decided that the family should move to London, and this was hastened by the rumour that her husband was potentially being targeted by the Fenians.

Her husband was a heavy drinker, but was called to the English and Irish bars, and founded the Sylvan Debating Club.

He bought Harmsworth a house first in Maida Vale, secondly at 2 Cumberland Place, Marble Arch, and finally Poynters Hall at Totteridge.

With her son Alfred and his wife, Harmsworth was hosted at the White House by President Theodore Roosevelt who was impressed by her.

Harmsworth died on 29 August 1925, and is buried beside her son Alfred in St Marylebone Cemetery, Finchley at his request.

Harold purchased a 15-acre site, formerly the Bethlem Royal Hospital, beside the Imperial War Museum in 1926 and founded the Geraldine Mary Harmsworth Park.