Diathrausta harlequinalis, the harlequin webworm moth, is a moth in the family Crambidae.

It was described by Harrison Gray Dyar Jr. in 1913.

It is found in North America in Mexico,[1] Arizona, California, Colorado, Connecticut, Florida, Maryland,[2] Massachusetts, Minnesota, New Mexico, North Carolina, Oklahoma, Ontario, Quebec, South Carolina, Tennessee and Texas.

Adults have been recorded from March to October.

[3] This Nomophilini-related article is a stub.