| Type: | Cardinal |
| Honorific Prefix: | His Eminence |
| Valentino Mastrozzi | |
| Cardinal-Priest of San Lorenzo in Panisperna | |
| Church: | Roman Catholic Church |
| Appointed: | 20 July 1801 |
| Term End: | 13 May 1809 |
| Predecessor: | Giovanni Battista Bussi de Pretis |
| Successor: | Pietro Gravina |
| Other Post: | Camerlengo of the College of Cardinals (1809) |
| Cardinal: | 23 February 1801 |
| Created Cardinal By: | Pope Pius VII |
| Rank: | Cardinal-Priest |
| Birth Name: | Valentino Mastrozzi |
| Birth Date: | 24 July 1729 |
| Birth Place: | Terni, Papal States |
| Death Place: | Rome, Papal States |
Valentino Mastrozzi (born 24 July 1729 in Terni, Italy, died 13 May 1809 in Rome) was a cardinal of the Catholic Church, and was a member of the Roman Curia.