Alexander Robert Reinagle (23 April 1756 – 21 September 1809) was an English-born American composer, organist, and theater musician.

He should not be confused with his nephew of the same name, Alexander Robert Reinagle (21 August 1799 – 6 April 1877),[1] also a composer and organist, who lived all his life in Britain.

At first, Reinagle made a living in the shipping industry, making several trips to the American colonies during the 1770s.

In 1786, Reinagle decided to try his fortune as a professional musician in the newly independent United States of America.

In Philadelphia, Reinagle worked closely with Thomas Wignell in producing opera ballets with the New Company, at the Chestnut Street Theater.

His earliest compositions, from his days in Edinburgh, include a set of duos for two cellos, Opus 2, and Variations on Famous Scots Tunes, published in Glasgow and later in Philadelphia.

Once in America, Reinagle continued to compose short pieces for special occasions, often with titles alluding to American personalities and ideas.