Formica lugubris is a species of ant found in Britain.
One of two Formica sp. to occur both in Britain and Ireland, this species has a scattered population, and is found in Northern England, Noth West Wales, Scotland and Ireland. This species is found in deciduous and conifierous woods, though sometimes found in open areas. This ant is similar to other 'wood' ants, and has an orange-brown thorax, and darker head and abdomen.