For the Poet Laureate of Milwaukee, see Antler (Poet).

Antlers are the large and complex horn-like appendages of deer, consisting of bony outgrowths from the head with no covering of keratin as is found in true horns. While an antler is growing it is covered with highly vascular skin called velvet , which supplies oxygen and nutrients to the growing bone; once the antler has achieved its proper size, the velvet is lost and the antler's bone dies. This dead bone structure is the mature antler. Antlers are shed after mating season and regrown each year.

The deer with the largest known antlers was the giant Irish deer, now extinct. The extant species with the largest antlers is currently the moose.

In most species, only males bear antlers. In the case of the reindeer, both sexes do. Due to its hardness, antler was an important material for tools from the Palaeolithic onwards (points, harpoons, needles etc). In the Neolithic, it was often used to haft stone axes. In early medieval times, it was the preferred raw material for combs.