450+ species Tetrastichus is a genus of hymenopteran insects of the family Eulophidae.

Tetrastichus planipennisi is a parasitoid of the emerald ash borer, a wood boring insect native to Asia which is an invasive species in North America.

T. planipennisi is being evaluated as a biological control agent.

The genus Tetrastichus parasitizes many different species of Lepidoptera, such as Pyralis farinalis.

This article about chalcid wasps of the family Eulophidae is a stub.