A new emerald ash borer (Coleoptera: Buprestidae) ectoparasitoid species, Spathius galinae Belokobylskij & Strazanac (Hymenoptera: Braconidae: Doryctinae), is described from the Russian Far East and South Korea. Molecular evidence supports that Russian and Korean specimens represent a single species and are closely related to two Asian species (S. agrili and S. generosus) that belong to the S. exarator species group. The morphological variation of adult S. galinae and its immature stages, distribution, life history, and relation to similar Asian Spathius species are discussed. The distribution of the new species may indicate this is one of the more cold hardy emerald ash borer parasitoids. A brief review of hymenopteran parasitoids of emerald ash borer and new host record, the first for Atanycolus nigriventris Vojnovskaja-Krieger (Braconidae: Braconinae), is reported.