Frances Walsingham, Countess of Essex and Countess of Clanricarde (1567 – 17 February 1633) was an English noblewoman. The daughter of Francis Walsingham, Elizabeth I's Secretary of State, she became the wife of Sir Philip Sidney at age 16. Her second husband was Robert Devereux, 2nd Earl of Essex, Queen Elizabeth's favourite, with whom she had five children. Shortly after his execution in 1601 she married her lover, Richard Burke, 4th Earl of Clanricarde, and went to live in Ireland.
She was the only child of Sir Francis Walsingham, Secretary of State for Queen Elizabeth I, and Ursula St. Barbe. A lady-in-waiting to Queen Elizabeth, she married Philip Sidney in 1583, who died three years later in 1586. In 1590 Frances' father also died, leaving her with an annuity of £300. She had one surviving child by Sidney: a daughter born in 1585 named Elizabeth after the Queen, who was one of the godparents. Elizabeth Sidney married Roger Manners, 5th Earl of Rutland, in March 1599 and died without issue in 1614.
In 1590 Frances married again, to Robert Devereux, 2nd Earl of Essex, to whom she had been committed by Philip at his death fighting overseas.