Holly provides dense cover and good nesting opportunities for birds, while its deep, dry leaf litter may be used by hedgehogs (Erinaceus europaeus) and small mammals for hibernation.

The flowers provide nectar and pollen for bees and other pollinating insects. The leaves are eaten by caterpillars of the holly blue butterfly (Celastrina argiolus), along with those of various moths, including the yellow-barred brindle (Acasis viretata), double-striped pug (Gymnoscelis rufifasciata) and the holly tortrix (Rhopobota naevana). The smooth leaves found at the tops of holly trees are a winter source of food for deer.