Thomas Southerne (1660 - May 22, 1746), English dramatist, was born at Oxmantown , near Dublin, in 1660, and entered Trinity College in 1676. Two years later he was entered at the Middle Temple, London.

His first play, The Persian Prince, or the Loyal Brother (1682), was based on a contemporary novel. The real interest of the play lay not in the plot, but in the political significance of the personages. Tachmas, the loyal brother, is obviously a flattering portrait of James II, and the villain Ismael is generally taken to represent Shaftesbury. The poet received an ensigns commission in Princess Annes regiment, and rapidly rose to the rank of captain, but his military career came to an end at the Revolution.

He then gave himself up entirely to dramatic writing. In 1692 he revised and completed Cleomenes for John Dryden; and two years later he scored a great success in the sentimental drama of The Fatal Marriage, or the Innocent Adultery (1694). The piece is based on Mrs Aphra Behn's The Nun, with the addition of a comic underplot. It was frequently revived, and in 1757 was altered by David Garrick and produced at Drury Lane. It was known later as Isabella, or The Fatal Marriage. The general spirit of his comedies is well exemplified by a line from Sir Anthony Love (1691) every day a new mistress and a new quarrel. This comedy, in which the part of the heroine, disguised as Sir Anthony Love, was excellently played by Mrs Mountfort, was his best. He scored another conspicuous success in Oroonoko, or The Royal Slave (1696). For the plot of this he was again indebted to the novel by Aphra Behn.

In his later pieces he did not secure any great successes, but he contrived to gain better returns from his plays than Dryden did, and he remained a favorite with his contemporaries and with the next literary generation. He died on the 22nd of May 1746.

His other plays are: The Disappointment, or the Mother in Fashion (1684), founded in part on the Curioso Imperlinente in Don Quixote; The Wives Excuse, or Cuckolds make themselves (1692); The Maids Last Prayer; or Any rather than fail (1692); The Fate of Capua (1700); The Spartan Dame (1719), taken from Plutarch's Life of Aegis; and Money the Mistress (1729).

His work is collected as Plays written by Thomas Southerne, with an Account of the Life and Writings of the Author (1774).