thumb|Pietro Alessandro Guglielmi
Pietro Alessandro Guglielmi (9 December 1728 – 19 November 1804) was an Italian opera composer of the classical period.
Biography
Guglielmi was born into the Guglielmi family of musicians in Massa.
He went to London, according to Charles Burney, in 1768, but according to Francesco Florimo in 1772, returned to Naples in 1777. He continued to produce operas at an astounding rate, but was unable to compete successfully with the younger masters of the day. In 1793 he became maestro di cappella at St Peter's, Rome, where he died in 1804.