An updated checklist of liverworts (Marchantiophyta) and hornworts (Anthocerotophyta) of Thailand is presented. The checklist is based on published literature and some recent collections. The liverwort and hornwort flora of Thailand consists of 386 species belonging to 90 genera in 37 families. The largest family is Lejeuneaceae (123 spp., 25 genera). The genera with over ten species are Cololejeunea (38 spp.), Plagiochila (37 spp.), Frullania (37 spp.), Bazzania (34 spp.), and Radula (21 spp.). Sixteen species are known only from Thailand, but no genera are endemic to the country. A new name (Cololejeunea gradsteinii M.J. Lai & R.L. Zhu, nom. nov.) and a new combination (Heteroscyphus inflatus (Steph.) S.C. Srivast. & A. Srivast. var. fragilissimus (N. Kitag.) M.J. Lai & R.L. Zhu, comb, nova) are proposed. Eleven species are reported for Thailand for the first time. Vegetation and bryofloristic accounts of Thailand are also discussed.