The Fort St. John Group is a stratigraphic unit of Lower Cretaceous age in the Western Canada Sedimentary Basin.

[2] It takes the name from the city of Fort St. John, British Columbia and was first defined by George Mercer Dawson in 1881.

The Fort St. John Group is mostly composed of dark shale deposited in a marine environment.

Bentonite is present in the shale, and it is interbedded with sandstone, siltstone and conglomerates.

The Fort St. John Group occurs in the subsurface in the Peace River Country of northeastern British Columbia and north-western Alberta, in southern Yukon and southern Northwest Territories.