Trichrysis cyanea is a species of cuckoo wasps, insects in the family Chrysididae.

This species is widespread in most of Europe and northern Africa throughout the Palearctic realm (central Asia, Siberia, Korea, China, and Japan).

[3] The posterior margin of the third tergite of the abdomen shows three small wide teeth.

Other recorded hosts are Hylaeus pectoralis, Heriades truncorum, Pemphredon lethifer, Stigmus pendulus, Ancistrocerus, Odynerus parietum, Cemonus unicolor, Nitela spinolae, Ectemnius rubicolus, Pison atrum, Psenulus pallipes, Osmia aenea, Osmia giraudi and Chelostoma florisomne.

The larvae are well recognizable by its gray-green body and brightly colored head and abdomen.