Collina d'Oro (English: Gold Hill) is a municipality in the district of Lugano in the canton of Ticino in Switzerland. It was formed from the 2004 union of the villages of Agra, Gentilino, and Montagnola.
Collina d'Oro has an area, as of 1997, of 5.64 square kilometers (2.2 sq mi). Of this area, 11.8% is used for agricultural purposes, while 51.5% is forested. Of the rest of the land, or 36.2% is settled (buildings or roads) and 0.05 km2 (12 acres) or 0.5% is unproductive land.
Lago di Muzzano is shared with the neighboring municipalities.
The village of Agra is located at an elevation of 570 m (1,870 ft) at the foot of Monte Crocione. Until the merger, the village of Gentilino included the north side of the Collina d'Oro valley, and the settlement of Viglio. The former municipality of Montagnola stretched over the central portion of the Collina d'Oro valley from the Bay of Agno to Pian Scairolo, and included a number of villages.
Montagnola was the home for over thirty years of the writer and Nobel Laureate Hermann Hesse until his death in 1962. He is buried in Gentino's San Abbondio cemetery.