| Serei Saophoan | |
| Other Name: | Sisophon |
| Native Name: | Central Khmer: សិរីសោភ័ណ |
| Settlement Type: | City |
| Pushpin Map: | Cambodia |
| Subdivision Type: | Country |
| Subdivision Name: |  Cambodia |
| Subdivision Type1: | Province |
| Subdivision Name1: | Banteay Meanchey |
| Subdivision Type2: | Municipality |
| Subdivision Name2: | Serei Saophoan |
| Leader Title: | Mayor |
| Leader Name: | Hil Raya |
| Population As Of: | 2019 |
| Population Footnotes: | [1] |
| Population Total: | 99,019 |
| Population Rank: | 4th |
| Timezone: | ICT |
| Utc Offset: | +07:00 |
| Coordinates: | 13.5833°N 161°W |
| Elevation M: | 15 |
Serei Saophoan (Central Khmer: សិរីសោភ័ណ in Central Khmer pronounced as /serəj saopʰɔən/) is the capital and largest city of the Banteay Meanchey Province and the fourth most populous city in Cambodia. The city separates Cambodia's National Highway 5 and National Highway 6. Its administrative name is "Serei Sophon" as used by the government. The more commonly used name Sisophon is derived from the Thai pronunciation Si Sophon when it was under the Thai rule. Another nickname "Svay" is used mainly by truck drivers, train drivers and workers transporting goods. The origin of the word "Svay" is unknown. Its population is 61,482 in the 1998 census, changing little to 61,631 in the 2008 census having been overtaken by Poipet in size.[2]
About forty minutes from Sisophon there is a Khmer Angkor temple ruin called Banteay Chmar.