Dorothy Spencer (née Sidney; later Smythe), Countess of Sunderland (5 October 1617 (baptised) – 5 February 1684), was the wife of Henry Spencer, 1st Earl of Sunderland, and the daughter of Robert Sidney, 2nd Earl of Leicester, and Lady Dorothy Percy. Lady Dorothy Sidney (or Sydney) was celebrated not only for her beauty but for wit, charm and intelligence. In about 1635, she rejected a marriage proposal from the poet Edmund Waller, who addressed verses to her under the nickname "Sacharissa" (which he based on the Latin word sacharum, meaning "sugar").