Old Saybrook
- Country: United States
- State: Connecticut
- Population: 2,039 (2010)
- Latitude: 41° 17.5' N (41.29177°)
- Longitude: 72° 22.6' W (-72.3762°)
- Elevation: 9 m/30 ft. above sea level
- Time zone: America/New_York (UTC -05:00); DST observed (UTC -04:00)
- Alternate names: Old Saybrook Center CDP, Pashbeshauke, Saybrook, Seabrook, Seabrooke, Zeebrugge