Girolamo Fantini was an Italian trumpeter and composer.
Little is known of Fantini's life. It is certain that he was a trumpeter 1631 of the court of the Grand Duke of Tuscany, Ferdinand II de 'Medici'.
In the summer of 1634 Fantini played in Cardinal Borghese on together with the organist of San Pietro in Rome, Girolamo Frescobaldi. It could be considered the first concert with trumpet and organ in the history of music. The French doctor and music biographer Pierre Bourdelot wrote to Marin Mersenne about Fantini: "Accompanied by Frescobaldi, Fantini has played in all chromatic tones."
Fantini is mainly known for his trumpet Method "by Modo imparare a sonare di tromba", which he published in Frankfurt in 1638.