Two new species of cavefishes from Mae Hong Son Province, northern Thailand represent the first record of cavefishes from that country. Nemacheilus oedipus n.sp. from Tham Nam Lang has degenerate eyes and is the first member of the Nemacheilinae with vestigial eyes and the seventh cavernicole. Homaloptera thamicola n.sp. from Tham Susa completely lacks eyes and is tentatively referred to Homaloptera, although it differs in details of mouth structure. It is the first blind cavernicolous representative of the Homalopterinae.