Cyperus papyrus (papyrus sedge, paper reed, Indian matting plant, Nile grass) is a species of aquatic flowering plant belonging to the sedge family Cyperaceae. It is a tender herbaceous perennial, native to Africa, and forms tall stands of reed-like swamp vegetation in shallow water.

Papyrus sedge (and its close relatives) has a very long history of use by humans, notably by the Ancient Egyptians—it is the source of papyrus paper, one of the first types of paper ever made. Parts of the plant can be eaten, and the highly buoyant stems can be made into boats. It is now often cultivated as an ornamental plant.

In nature, it grows in full sun, in flooded swamps, and on lake margins throughout Africa, Madagascar, and the Mediterranean countries.

C. papyrus and the dwarf cultivar C. papyrus 'Nanus' have gained the Royal Horticultural Society's Award of Garden Merit.