Diana Russell, Duchess of Bedford

Lady Diana Spencer and her mother, the Countess of Sunderland.

Diana Russell, Duchess of Bedford (formerly Lady Diana Spencer) (1710–1735) was a prospective Princess of Wales and, later, Duchess of Bedford.

Diana was the daughter of Charles Spencer, 3rd Earl of Sunderland and Lady Anne Churchill, daughter of John Churchill, 1st Duke of Marlborough. She spent much of her youth living with her maternal grandmother, Sarah Churchill, Duchess of Marlborough, at Cumberland Lodge in Old Windsor.

The Duchess encouraged her to hope for a royal alliance with the Prince of Wales, Frederick, which was prompted more by the prince's hope of an increased financial allowance than from any mutual affection. However, the idea of such a marriage was quashed by King George II and Robert Walpole, and Lady Diana married, in 1731, John Russell, 4th Duke of Bedford. Frederick married Princess Augusta of Saxe-Gotha.

She was the mother of John Russell, Marquess of Tavistock (6 Nov 1732-6 Nov 1732). She died on 27 September 1735 at Southampton House, London, England, from tuberculosis, without surviving issue. She was buried on 9 October 1735 at Chenies, Buckinghamshire, England.