An investigation of bryophyte diversity of Khao Soi Dao wildlife sanctuary, Chanthaburi Province, Thailand was carried out in April 2013. In total, 387 specimens were enumerated, consisting of 103 species (45 liverworts, 1 hornwort, 57 mosses), 67 genera (25 liverworts, 1 hornwort, 41 mosses), and 38 families (14 liverworts, 1 hornwort, 23 mosses), excluding those as yet unidentified to species. Among these, four species of mosses, including Clastobryum glabrescens (Z.Iwats.) B.C.Tan, Z.Iwats. & D.H.Norris, Macromitrium lorifolium Paris & Broth., Pterobryopsis gedehensis M.Fleisch., and Radulina borbonica (Bél.) W.R.Buck, are newly reported to Thailand in this paper. [ABSTRACT FROM AUTHOR]