| Old Slains Castle | |
|---|---|
 The remains of Old Slains Castle | |
| Coordinates | 57°21′39″N 1°54′52″W / 57.3609°N 1.91438°W |
| OS grid reference | NK052300 |
| Built | 13th-century |
| Built for | Comyn, Earl of Buchan |
  Location in Aberdeenshire | |
Slains Castle (otherwise known as Old Slains Castle) is a ruined castle near Collieston in Aberdeenshire, Scotland. It is not to be confused with New Slains Castle, a separate building located five miles (eight kilometres) northeast. Built in the 13th century, it was partly destroyed in 1594.