The Ribbon-tailed Astrapia also known as Shaw Mayer's Astrapia, Astrapia mayeri is a medium-sized, up to 32cm long (without including the tail of the male, which can be over 1 meter), velvet black bird of paradise. The male has an iridescent olive green and bronze plumage, and is adorned with ornamental "ball" plume above its bill and two extremely long, ribbon-like white tail feathers. The female is a brown bird with an iridescent head.

One of the most spectacular bird of paradise, the male Ribbon-tailed Astrapia has the longest tail feathers in relation to body size of any bird, over three times the length of its body.

The Ribbon-tailed Astrapia is distributed and endemic to subalpine forests in western part of the central highlands of Papua New Guinea. Like many other ornamental birds of paradise, the male is polygamous. The Ribbon-tailed Astrapia is the latest bird of paradise to be discovered.

The scientific name commemorates the great naturalist and New Guinea explorer Fred Shaw Mayer, who was believed to have discovered the bird in 1938. However, it is now believed a Mr. Hides discovered the bird first, while Mayer took interest afterwards.

Due to habitat lost and hunted for its plumes, the Ribbon-tailed Astrapia is listed as Near Threatened on the IUCN Red List of Threatened Species. It is listed on Appendix II of CITES.