Thomas Augustine Arne (March 12, 1710 – March 5, 1778) was an English composer, best known for the popular patriotic song, 'Rule Britannia', which is still frequently sung, notably at the Last Night of the Proms, and also his musical settings of songs from the plays of William Shakespeare.

Arne was born in the Covent Garden area of London, to a family that had prospered in the upholstery business. He was educated at Eton College, and was interested in music from his earliest youth. A chance meeting with Michael Festing gave him the opportunity to indulge his interest, though his father still wanted him to become a lawyer.

Arne's sister, Susannah Maria Arne, was a famous contralto who performed in some of his works, including his first opera, Rosamund, performed in 1733. She had been taught to sing by her brother, and had first performed with him in 1732, along with their brother Richard. In 1736, Arne married another singer, Cecilia Young (whose sister, Isabella, married the composer John Frederick Lampe). Arne's operas and masques became very popular, and he received the patronage of Frederick, Prince of Wales, at whose country home, Cliveden, the Masque of Alfred, featuring 'Rule, Britannia', was first performed.

In 1750, after an argument with David Garrick, Susannah left Drury Lane for Covent Garden Theatre, and her brother followed. In 1755, he separated from his wife, who, he alleged, was mentally ill. He had in the meantime begun a relationship with one of his pupils, a Miss Brent, who performed in some of his works. She later married a violinist. In 1777, shortly before his death, Arne and his wife were reconciled. They had one son, Michael Arne.

He is buried at St Paul's, Covent Garden, London.