Ballao () is a village and comune (municipality) in the Metropolitan City of Cagliari in the autonomous island region of Sardinia in Italy, located about northeast of Cagliari, in the Gerrei traditional subregion. It has inhabitants.
Ballao borders the municipalities of Armungia, Escalaplano, Goni, Perdasdefogu, San Nicolò Gerrei, Silius, and Villaputzu.
It was founded around 1300, when the inhabitants of the ancient hill village of Nuraxi moved in the nearby plain, nearer to the Flumendosa river, to improve their agricultural output. It is home to the Funtana Coberta, a Bronze Age archaeological site.