Uloborus walckenaerius is a spider in the family Uloboridae. Like all spiders in this family, they do not have venom glands and kill their prey by crushing with over 140 metres of thread.
Females grow up to 6 mm, males up to 4 mm. It has a dark grey prosoma, covered with white hairs, leaving some dark bands uncovered. The spider lives in warm, open terrain, like heathland, and weaves horizontal cribellate webs close to the ground. A stabilimentum is sometimes present.
Named in honor of Charles Athanase Walckenaer.