Pietro Alessandro Gaspare Scarlatti (2 May 1660 – 22 October 1725) was an Italian Baroque composer, known especially for his operas and chamber cantatas. He is considered the founder of the Neapolitan school of opera. He was the father of two other composers, Domenico Scarlatti and Pietro Filippo Scarlatti.

Scarlatti was born in Palermo (or in Trapani), then part of the Kingdom of Sicily. He is generally said to have been a pupil of Giacomo Carissimi in Rome, and some theorize that he had some connection with northern Italy because his early works seem to show the influence of Stradella and Legrenzi. The production at Rome of his opera Gli equivoci nel sembiante (1679) gained him the support of Queen Christina of Sweden (who at the time was living in Rome), and he became her maestro di cappella. In February 1684 he became maestro di cappella to the viceroy of Naples, perhaps through the influence of his sister, an opera singer, who might have been the mistress of an influential Neapolitan noble. Here he produced a long series of operas, remarkable chiefly for their fluency and expressiveness, as well as other music for state occasions.