The blue background of this shield represents the clear skies of the Northwest Territories, while the mining tower in the centre represents the mineral wealth that built the city. On either side of the tower are a gold maple leaf (representing Canada, and the gold mined in the area) and gold mining tools (again, mineral wealth). Below the tower is part of Great Slave Lake and one of the boats which connect Yellowknife to other communities during the summer. Above the tower shine the northern lights (although I've never seen them in a blue sky before). As a crest is a yellow knife (the emblem of the First Nation tribe that the city is named after), with wings to represent the aviation which allows the city to retain its connection with the rest of the world regardless of the road and river conditions.

This city actually has a quite simple flag (blue, with a white polar bear), that would make a much better coat of arms than what they use.