The diademed sandpiper-plover or diademed plover (Phegornis mitchellii) is a Near Threatened species of bird in subfamily Charadriinae of family Charadriidae. It is found in Argentina, Bolivia, Chile, and Peru.
The diademed sandpiper-plover is the only member of its genus and has no subspecies. The species has at times been thought to belong to family Scolopacidae (the sandpipers) but genetic data place it firmly with other plovers in family Charadriidae. It appears to be most closely related to several Australian and New Zealand plovers of genera Elseyornis, Peltohyas, Anarhynchus, and Pedionomus.
The diademed sandpiper-plover is 16.5 to 19 cm long and weighs 28 to 46 g. The sexes are alike. Their bill is black and slightly decurved. Their legs and feet are orange. The adult's face is black with a wide white supercilium than extends around the back of the head. Their crown is black, their nape bright rufous, most of their upperparts dark brownish gray, and their rump and uppertail coverts are black. The tail is black with white tips to the feathers. Their throat is white, their chest, belly, and flanks are barred black and white, and their vent and undertail coverts are unmarked white. Juveniles are much duller than adults. Their upperparts are mostly brownish gray with cinnamon speckles and bars. Their supercilium is grayish and their nape is washed with cinnamon or rufous.