The meridian 125° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, North America, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole.
The 125th meridian west forms a great circle with the 55th meridian east.
Starting at the North Pole and heading south to the South Pole, the 125th meridian west passes through:
| Co-ordinates | Country, territory or sea | Notes |
|---|---|---|
| Arctic Ocean | ||
| Beaufort Sea | ||
| Northwest Territories — Banks Island | ||
| Amundsen Gulf | ||
| Northwest Territories — passing through the Great Bear Lake Yukon — from British Columbia — from, the mainland, Raza Island and Cortes Island | ||
| Strait of Georgia | ||
| British Columbia — Vancouver Island, through Courtenay | ||
| Pacific Ocean | Passing just west of Cape Alava, Washington, (at) Passing just west of Ducie Island, (at) | |
| Southern Ocean | ||
| Antarctica | Unclaimed territory | |