Mantaritza Biosphere Reserve (Bulgarian: Биосферен резерват "Мантарица") is situated to the north of Golyama Syutka Peak in the Rhodope Mountains in Bulgaria, and covers an area of 1319,9 hectares.

The reserve was established in 1968 to protect the old coniferous forests and the biotopes of the Western capercaillie (Tetrao urogalus).

The reserve is situated in the Bulgarian Floristic sub-region of West Rhodope within the Central European mountain biotic province.

The varied fauna includes brown bear (Ursus arctos), red deer (Cervus elaphus), roe deer (Capreolus capreolus), wild boar (Sus scrofa), pine marten (Martes martes), European badger (Meles meles), hazel grouse (Bonasa bonasia), black woodpecker (Dryocopus martius) and crested tit (Parus cristatus).

Before the biosphere reserve was designated in 1977, small-scale selective cutting took place and water reservoirs were constructed.