Orelyak (Bulgarian: Ореляк) is a nature reserve in the central section of the Pirin mountain range in south-western Bulgaria.

It was declared on 22 February 1985 to protect old growth beech forests it the vicinities of Mount Orelyak (2,099 m), the highest summit in Central Pirin.

In the western sections at about 1700 m altitude there are also small patches of Macedonian pine (Pinus peuce).

Orelyak reserve is home to a number Bulgarian and Balkan endemic herbaceous species, including Pirin tea (Sideritis scardica), Draba scardica, Achillea chrysocoma, Saxifraga ferdinandi-coburgi, Viola grisebachiana, Polygala rhodopaea, Arabis ferdinandi-coburgii, Thymus perinicus, etc.

Typical animals include brown bear, gray wolf, red fox, wild boar, roe deer, Greek stream frog, fire salamander, etc.