Nine species in five genera of Nematinae are recorded for the first time from Thailand: Trichiocampus namtokensis, n. sp., Dineura sharkeyi, n. sp., Moricella rueaensis, n. sp., Nematus saodaoi, n. sp., Pristiphora chalybeata Benson, Pristiphora ettera, n. sp., Pristiphroa inthanoni, n. sp., Pristiphora annetna, n. sp., and Pristiphora phahompoki, n. sp. A key is given for the genera and species of Thailand. New records and description of the male are given for P. borneensis Forsius from Sabah, Malaysia, and a new record is given for P. sinensis Wong from China.