Six species of Aulacidae are reported new to Thailand and Laos. Pristaulacus exuberans Turrisi and Smith, sp. nov. from Thailand, Pristaulacus matteinii Turrisi and Smith, sp. nov. from Laos and Thailand, and Pristaulacus perfidus Turrisi and Smith, sp. nov. from Thailand, are described and illustrated, and compared with most related species. Pristaulacus nigripesKieffer, 1911, is confirmed from Thailand, and Aulacus canlaon Smith, 2017 and Pristaulacus rufobalteatusCameron, 1907, are new records for Thailand. Fourteen species are now known in Thailand.