O. exigua may refer to:
Ophiothrix exigua, a brittle star Oplitis exigua, a mite with a single pair of spiracles positioned laterally on the body Oreodera exigua, a longhorn beetle Orthomecyna exigua, a moth endemic to Hawaii Oryzopsis exigua, a true grass Oscinella exigua, a European fly Osminia exigua, a clearwing moth Ozola exigua, a geometer moth