Edwina Cynthia Annette Mountbatten, Countess Mountbatten of Burma (née Ashley; 28 November 1901 – 21 February 1960), was an English heiress, socialite, and relief worker. As the wife of Rear Admiral Louis Mountbatten, 1st Earl Mountbatten of Burma, she served as the last vicereine of India during the reign of George VI. She was a close relative by marriage to the British royal family. She was appointed a Commander of the Order of the British Empire in 1943 and a Dame Commander of the Royal Victorian Order in 1946 for her efforts with the St John Ambulance Brigade and the British Red Cross during World War II.

Edwina Cynthia Annette Ashley was born in 1901, the elder daughter of Wilfrid Ashley (later 1st Baron Mount Temple), who was a Conservative member of Parliament. Her younger sister was Mary Ashley (Lady Delamere). Patrilineally, she was a great-granddaughter of the reformist 7th Earl of Shaftesbury. Edwina's mother, Amalia Mary Maud Cassel (1880–1911), was the only child of the international magnate Sir Ernest Cassel (1852–1921), friend and private financier to the future King Edward VII. Cassel had been born in Cologne, Prussia, of Jewish origin. He was one of the richest and most powerful men in Europe.

After Wilfred Ashley's remarriage in 1914 to Molly Forbes-Sempill (ex-wife of Rear-Admiral Arthur Forbes-Sempill), Edwina Ashley was sent away to boarding schools, first to the Links in Eastbourne, then to Alde House in Suffolk, at neither of which was she a willing pupil. Edwina was unhappy during the time because, in addition to a sour relationship with her stepmother, she was bullied at school on account of her grandfather being rich, German, and Jewish. She later described her experience at school as 'sheer hell'. Her grandfather, Sir Ernest, solved the domestic dilemma by inviting her to live with him and, eventually, to act as hostess at his London residence, Brook House. Later, his other mansions, Moulton Paddocks and Branksome Dene, would become part of her inheritance from him.^{[citation needed]}

Edwina Ashley first met Louis Mountbatten, a relative of the British royal family and a nephew of Empress Alexandra of Russia, at a ball at Claridge's hotel in October 1920. By this time, she was a leading member within London society.

Ashley and Mountbatten married on 18 July 1922 at St Margaret's, Westminster. The wedding attracted more than 8,000 people, including members of the royal family such as Queen Mary, Queen Alexandra, and the Prince of Wales (the future King Edward VIII), who served as the groom's best man. It was dubbed "wedding of the year". There followed a honeymoon tour of European royal courts and America which included a visit to Niagara Falls (because "all honeymooners went there"). During their honeymoon in California, the newlyweds starred in a silent home movie by Charlie Chaplin called Nice And Friendly, which was not shown in cinemas.

Following the death of her maternal grandfather in 1921, Edwina inherited a life interest in a Trust Fund created from a 25/64 share of her granfather's residuary estate (estimated at £7,330,000 - equivalent to about £390 million in 2023); the net amount left in trust to Edwina amounted to approximately £1,600,000 after the deduction of specific bequests, administration costs and death duties.

Edwina also inherited her grandfather's palatial London townhouse, Brook House, at a time when her future husband's salary as Royal Navy lieutenant was £310 a year (equivalent to £16,400 in 2023), which was doubled by his private income. Later, she inherited the country seat of Broadlands, Hampshire, from her father, Lord Mount Temple. Edwina's husband Lord Mountbatten reportedly confided to their older daughter that the couple sometimes struggled to spend their £60,000 post-tax annual income during the years prior to the Second World War.

By the end of the Second World War in Europe, the highest rate of income tax in Great Britain had risen to 19s 6d on £1 (97.5%), which reduced the post-tax income Lord and Lady Mountbatten enjoyed from the latter's trust fund to £4,500. The Mountbattens sought a Private members' bills in the Parliament of the United Kingdom, and in 1949 the "Mountbatten Estate Bill" was introduced to the British Parliament to amend the terms of the Edwina's Trust Fund to remove the restrictions her grandfather's will placed on her borrowing on the capital assets or anticipation of future income from her Trust. The justification for the bill was made on the basis that Lord and Lady Mountbatten undertook an exceptionally large number of public duties which they argued as a significant drain on their private wealth. In an address to the House of Lords committee, Edwina's representative Sir Walter Monckton KC noted that Edwina had enjoyed a post-tax income of about £40,000 prior to the War.