Gergei is a comune, or municipality, located in the Italian region of Sardinia. It is situated within the Metropolitan City of Cagliari, positioned approximately 50 kilometres (31 mi) north of the city of Cagliari.
As of December 31, 2004, the municipality covered an area of 36.1 square kilometres (13.9 mi2) and had a population of 1,413 residents.