| San Martino Siccomario | |
| Official Name: | Città di San Martino Siccomario |
| Native Name: | San Martin |
| Coordinates: | 45.15°N 17°W |
| Region: | Lombardy |
| Province: | Pavia (PV) |
| Frazioni: | Bivio Cava, La Madonna, Paradiso Nuovo, Paradiso Vecchio, Santa Croce |
| Mayor: | Alessandro Zocca |
| Area Total Km2: | 14.3 |
| Population Footnotes: | [1] |
| Population Total: | 6036 |
| Population As Of: | 1 January 2015 |
| Population Demonym: | Sammartinesi |
| Elevation M: | 63 |
| Saint: | St. Martin |
| Day: | August 5 |
| Postal Code: | 27028 |
| Area Code: | 0382 |
San Martino Siccomario (San Martin) is a comune in the Province of Pavia in the Italian region Lombardy, located about 35 km south of Milan and about 4 km southwest of Pavia. It is now effectively part of Pavia metropolitan area.
San Martino Siccomario borders the following municipalities: Carbonara al Ticino, Cava Manara, Pavia, Travacò Siccomario.
According to legend, St. Martin of Tours lived here as a child; in the 9th century a monastery entitled to the saint existed here. Later it was a fief of the Beccaria family (see Montù Beccaria) and other families. In 1743 it was annexed to the Kingdom of Sardinia (Piedmont), remaining the boundary with the Austrian-controlled Lombardy-Venetia until 1859.
On the Gravellone stream, in 1848, king Charles Albert of Sardinia assigned for the first time to his army the Tricolore, which was to become Italy's flag.