Gonnesa is a comune (municipality) in the Province of South Sardinia in the Italian region Sardinia, located about 60 kilometres (37 mi) west of Cagliari and about 14 kilometres (9 mi) northwest of Carbonia, in the Iglesiente subregion.

During the 19th century its territory was affected by the resumption of mining which contributed significantly to its population growth .

In its territory there is an important archaeological site, the nuraghe Seruci, and beach of almost 4 kilometres (2 mi) along which it is possible to surf, especially in a spot called Funtanamare.

The other two spots are called Plag' 'e Mesu ("Middle Beach" in Sardinian language, and Porto Paglia.

Gonnesa borders the following municipalities: Carbonia, Iglesias, Portoscuso.