Alfonso Fontanelli was an Italian composer. He served various members of the Este family from no later than 1586 until 1620, with occasional short interruptions and much traveling; then took holy orders; lived in Ferrara, Modena, Rome, and Florence. The style of his madrigals, most published in two complete books (1595 and 1604), reflects his friendship with Gesualdo and his long association with the Ferrarese court.