The Nauru Reed Warbler (Acrocephalus rehsei) is a species of Old World warbler and the only bird species endemic to the island Nauru. The species is listed as vulnerable by the IUCN, as its habitat on Nauru may be a threat.

It is 15 centimeters long, it has a straight beak and its body is greyish-olive above with an off-white below chest and a white eyebrow.