Ophryophryne synoria is a species of frog in the family Megophryidae. It is only known from its type locality in eastern Cambodia (Keo Seima Wildlife Sanctuary, Mondulkiri Province) and from southern Vietnam (Bình Phðá»Âc and ÃÂá»Âng Nai Provinces). Common names O'Reang horned frog and O'Reang mountain toad have been proposed for it.
Ophryophryne synoria occurs in hilly mixed and evergreen forests at elevations of above sea level. It is present in several protected areas: its type locality, Keo Seima Wildlife Sanctuary in Cambodia, and Bù Gia MáºÂp and Cát Tiên National Parks in Vietnam.