Thallophaga hyperborea, the northern thallophaga, is a moth of the family Geometridae. The species can be found in British Columbia. The wingspan is 30–37 millimetres (1.2–1.5 in). The moths fly from April to May depending on the location. The larvae feed on western hemlock, Douglas fir, red cedar and other firs. The moth is also recorded on willow and alder as well as other conifers.