Leonardo Leo (5 August 1694 – 31 October 1744), more correctly Lionardo Oronzo Salvatore de Leo, was a Neapolitan Baroque composer.
Leo was born in San Vito degli Schiavoni (current San Vito dei Normanni, province of Brindisi), then part of the Kingdom of Naples.
He became a student at the Conservatorio della Pietà dei Turchini at Naples in 1703, and was a pupil first of Francesco Provenzale and later of Nicola Fago. It has been supposed that he was a pupil of Pitoni and Alessandro Scarlatti, but he could not possibly have studied with either of these composers, although he was undoubtedly influenced by their compositions. His earliest known work was a sacred drama, L'infedelta abbattuta, performed by his fellow-students in 1712.
In 1714 he produced, at the court theatre, an opera, Pisistrato, which was much admired. He held various posts at the royal chapel, and continued to write for the stage, besides teaching at the conservatory. After adding comic scenes to Francesco Gasparini's Bajazette in 1722 for performance at Naples, he composed comic operas in Neapolitan such as La’mpeca scoperta in 1723, and L'Alidoro in 1740.
His most famous comic opera was Amor vuol sofferenze (1739), better known as La Finta Frascatana, highly praised by De Brosses. He was equally distinguished as a composer of serious opera, Demofoonte (1735), Farnace (1737) and L'Olimpiade (1737) being his most famous works in this branch, and is still better known as a composer of sacred music. He died of a stroke while engaged in the composition of new arias for a revival of La Finta Frascatana.