- Source: Costanzi
Costanzi is a surname. Notable people with the surname include:
Carlo Costanzi (1705–1781), Italian gem engraver
Giovanni Costanzi (1674–1754), Italian gem engraver
Giovanni Battista Costanzi (1704–1778), Italian composer and cellist
Giulio Costanzi (1875–1965), Italian spaceflight scientist
Placido Costanzi (1702–1759), Italian painter
Tommaso Costanzi (1700–1747), Italian gem engraver