| Type: | Cardinal |
| Tolomeo Gallio | |
| Cardinal-Bishop of Ostia e Velletri | |
| Church: | Catholic Church |
| Term: | 1603–1607 |
| Predecessor: | Alfonso Gesualdo di Conza |
| Successor: | Domenico Pinelli |
| Cardinal: | 3 February 1607 |
| Rank: | Cardinal Bishop |
| Birth Date: | 25 September 1527 |
| Birth Place: | Cernobbio |
| Death Date: | 3 or 4 February 1607 (age 79) |
| Death Place: | Rome, Italy |
| Nationality: | Italian |
Tolomeo Gallio (also spelled Gallo and Galli; 25 September 1527 - 3 or 4 February 1607) was an Italian Cardinal.
In the time of Pope Gregory XIII, he acted as papal secretary of state (in office 1572 to 1585), having a key role in the curia.[1]
He built the Villa d'Este, in his birthplace Cernobbio, in 1568, as a summer residence; and the Palazzo Gallio of Gravedona.
He was bishop of Martirano in 1560, archbishop of Manfredonia in 1562, bishop of Albano in 1587, bishop of Sabina in 1589, bishop of Frascati in 1591, bishop of Porto e Santa Rufina in 1600, bishop of Ostia in 1603.
Tolomeo in 1595 acquired the County of Alvito (later Duchy) in southern Lazio, which he assigned to his nephew Tolomeo; the Gallio family held the fief until 1806.