Petreu (Hungarian: Monospetri) is a commune in Bihor County, Crișana, Romania with a population of 3,080 people as of 2021.

It is composed of four villages: Abrămuț (Vedresábrány), Crestur (Apátkeresztúr), Făncica (Érfancsika), and Petreu.

National road DN19B [ro], which runs from Săcueni on the Hungarian border to Șimleu Silvaniei in Sălaj County, passes through the Crestur and Petreu villages.

Just to the east of Petreu is the city of Marghita; the capital of Bihor County, Oradea, is 52 km (32 mi) to the southwest.

The commune was called Abrămuț and its administrative seat was located in that village until 2022, when a law changed the name.