Frances Stevenson, Countess Lloyd-George of Dwyfor, CBE (7 October 1888 – 5 December 1972) was the mistress, personal secretary, confidante and second wife of British Prime Minister David Lloyd George.

Frances Stevenson was born in London. She was educated at Clapham High School and Royal Holloway College, where she graduated with a Classics degree in 1910. In July 1911 Lloyd George, then Chancellor of the Exchequer, hired Stevenson as a governess for his youngest daughter Megan. Lloyd George and Stevenson were soon attracted to each other. Although Stevenson, who wanted a conventional marriage and many children, hesitated about becoming the mistress of a married man, she agreed to become Lloyd George's personal secretary on his terms, which included a sexual relationship, in 1913. Lloyd George lived in a draughty London house, came home to an empty flat, so they became lovers in 1913, while his wife was still living at Criccieth.

She was created a Commander of the Order of the British Empire in 1918 and accompanied Lloyd George to the Paris Peace Conference of 1919. The delegates were under the impression she was still just his secretary. Stevenson chose the location and supervised the construction of Lloyd George's country house in Churt, Surrey.

She also arranged and collated Lloyd George's extensive archive of personal and political papers so that he could write his War Memoirs. After having been persuaded by Lloyd George to have two abortions, Stevenson gave birth to a daughter, Jennifer, in 1929. Although Stevenson had been having an affair with Thomas Frederic Tweed, a novelist who was one of Lloyd George's political advisers, Lloyd George was probably the father of Stevenson's child.

Two years after the death of Lloyd George's wife Margaret, Stevenson married Lloyd George on 23 October 1943 despite the disapproval of Lloyd George's children from his first marriage. Less than 18 months later, Lloyd George died on 26 March 1945.

Frances Stevenson, now the Dowager Countess Lloyd-George of Dwyfor, lived at Churt for the rest of her life, devoting her time to her family, charitable activities, perpetuating the memory of Lloyd George and writing. Her memoirs The Years That Are Past was published in 1967, and her diary of her life with Lloyd George was published in 1971.