Siwanoy
| Map of Long Island Sound showing approximate location of known Siwanoy settlements | |
| Regions with significant populations | |
|---|---|
| United States (New York) | |
| Languages | |
| Munsee | |
| Religion | |
| Indigenous religion | |
| Related ethnic groups | |
| Wappinger, Lenape, Wecquaesgeek, Mahican | 
The Siwanoy (/ˈsaɪwənɔɪ/) were an Indigenous American band of Munsee-speaking people, who lived in Long Island Sound along the coasts of what are now The Bronx, Westchester County, New York, and Fairfield County, Connecticut. They were one of the western bands of the Wappinger Confederacy. By 1640, their territory (Wykagyl) extended from Hell Gate to Norwalk, Connecticut, and as far inland as White Plains; it became hotly contested between Dutch and English colonial interests.: 28