| Kastanoussa | |
| Name Local: | Καστανούσσα |
| Type: | community |
| Periph: | Central Macedonia |
| Periphunit: | Serres |
| Municipality: | Sintiki |
| Population: | 635 |
| Population As Of: | 2021 |
| Elevation: | 274 |
| Coordinates: | 41.2736°N 22.8925°W |
| Postal Code: | 620 55 |
| Area Code: | +30 23270 |
| Licence: | EP |
Kastanoussa (Greek, Modern (1453-);: Καστανούσσα), known before 1926 as Palmes (Greek, Modern (1453-);: Πάλμες|links=no),[1] is a village and a community in Serres with a population of 635 inhabitants as recorded in the 2021 census. The village and community belongs to the municipality of Sintiki.
The village is located in the southern foothills of Belasitsa, near the borders with North Macedonia and Bulgaria.
In 1891 Georgi Strezov wrote:
According to the statistics of Vasil Kanchov ("Macedonia. Ethnography and Statistics") by 1900 "Palmesh" ("Palmesha") is a Bulgarian Muslims' settlement . 1150 Bulgarian Muslims were living there at the time.
During the First Balkan War the village was under Bulgarian control, but after the Second Balkan War in 1913 it was incorporated within Greece.