The Collegiata di Santa Maria Assunta or Duomo di San Gimignano is a Roman Catholic collegiate church and minor basilica in San Gimignano, in Tuscany in central Italy. It contains important cycles of Renaissance frescoes by artists including Domenico Ghirlandaio, Benozzo Gozzoli, Taddeo di Bartolo, Lippo Memmi and Bartolo di Fredi. It falls within the UNESCO World Heritage Site of the "Historic Centre of San Gimignano", with its frescoes being described by UNESCO as "works of outstanding beauty".

San Gimignano is a small walled medieval hill town in the province of Siena, Tuscany, north-central Italy. Known as the Town of Fine Towers, San Gimignano is famous for its medieval architecture, unique in the preservation of about a dozen of its tower houses, which, with its hilltop setting and encircling walls, form "an unforgettable skyline". Within the walls, the well-preserved buildings include notable examples of both Romanesque and Gothic architecture, with outstanding examples of secular buildings as well as churches. The Palazzo Comunale, the Collegiate Church and Church of Sant' Agostino contain frescos, including cycles dating from the 14th and 15th centuries. The "Historic Centre of San Gimignano" is a UNESCO World Heritage Site. The town also is known for saffron, the Golden Ham, pecorino cheese and its white wine, Vernaccia di San Gimignano, produced from the ancient variety of Vernaccia grape which is grown on the sandstone hillsides of the area.