O. orientalis may refer to: Octoknema orientalis, a plant species endemic to Tanzania Onchidella orientalis, an air-breathing sea slug species Orosius orientalis, the common brown leafhopper, a leafhopper species found in Australia Ovis orientalis (or O. aries orientalis), the mouflon, a wild sheep species Oxychilus orientalis, an air-breathing land snail species found in Slovakia
See also Orientalis (disambiguation)