| Alert Stack | |
| Coordinates: | -48.0375°N 166.575°W |
| Area Ha: | 14 |
| Length M: | 400 |
| Width M: | 400 |
| Location: | Snares Islands |
| Country: | New Zealand |
| Country Admin Divisions Title: | Region |
| Country Admin Divisions: | New Zealand outlying islands |
| Population: | uninhabited |
Alert Stack is an outlying island of New Zealand. It is a part of the Snares Islands, lying southwest of North East Island.[1] There is an estimated five pairs of nesting Antarctic tern .[2]