Natural plants of Camellia (Theaceae) in Thailand are taxonomically revised with a key, a distribution map, descriptions, specimens examined, and figures of living plants and/or dry specimens. Nine taxa comprising seven species and two varieties are recognized, including C.caudata , C.connata , C.furfuracea , C.kissi , C.kissivar.confusa, C.laotica , C.sinensisvar.assamica, C.suddeeana , and C.taliensis . Camelliacaudata and C.laotica are new records to Thailand, and C.connata and C.suddeeana are endemic to the country. Formerly recorded C.pleurocarpa and C.tenii are excluded from Thai flora because of misidentification, and C.oleifera and C.sinensis are merely cultivated in the country. Morphological descriptions of C.connata and C.laotica are improved based on additional collections examined.