Clostera albosigma, the sigmoid prominent, is a moth of the family Notodontidae.

It is found in North America from Newfoundland west to Vancouver Island, north to the Great Slave Lake and the Northwest Territories and south to at least Missouri.

The moth flies from May to August depending on the location.

The larvae feed on poplar and willow.

This article on a moth of the family Notodontidae is a stub.