Gregorio de Ferrari (c. 1647 – 1726) was an Italian Baroque painter of the Genoese school.
De Ferrari was born in Porto Maurizio. He came to Genoa to study law but instead became a painter. He apprenticed with Domenico Fiasella from 1664–69, and in this period he may have painted in the style of Giovanni Andrea de Ferrari and Giovanni Battista Casone. He assisted Fiasella on the altarpiece St Clare Repulsing the Saracens (1667) for the parish church in Montoggio. He travelled to Parma (1669-1673), where he worked in quadratura frescoes. He ultimately joined his father-in-law, Domenico Piola, in the prolific studio known as Casa Piola. They were both active in the decoration of the Basilica della Santissima Annunziata del Vastato. They worked in styles that blended Cortona, Correggio, and Castiglione's styles. His Death of Santa Scolastica in San Stefano of Genoa is considered his masterpiece. One of his pupils was Francesco Costa. Among the children of Gregorio and his wife, Margherita Piola, was the painter Lorenzo de' Ferrari.