Thelma Cazalet-Keir CBE (née Cazalet; 28 May 1899 – 13 January 1989) was a British feminist and Conservative Party politician.

Her father was a wealthy socialite, and in her childhood she met many leading figures of the day, including Rudyard Kipling, Sylvia Pankhurst and Beatrice Webb.

Cazalet entered local politics in Kent, where the family had their country house, Fairlawne, in Shipbourne.

She was soon back in the Islington East constituency, contesting the general election in October of the same year, when she gained the seat for the Conservatives from the by-election winner, Labour's Leah Manning.

Her proposed amendment to the Education Bill, demanding for equal pay for women teachers, passed by one vote on 28 March 1944.

For many years, she lived in Kent, at Raspit Hill, not far from her childhood home, but when she was widowed, in 1969, she sold the house and its 75 acres to Malcolm MacDonald, and moved to her London flat in Belgravia.