San Ignacio Cayo is a town in the west of the nation of Belize; it is capital of Belize's Cayo District.

San Ignacio Cayo is on the banks of the Macal River, a branch of the Belize River, about 72 miles west of Belize City and 22 miles from Belmopan. The population is largely Maya Indian and Mestizo, with some Lebanese.

San Ignacio absorbed the formerly separate village of Santa Elena, across the Macal River; the river is spanned by the Hawkesworth Suspension Bridge. The ancient Maya ruins of Xunantunich and Cahal Pech are near by.

According to the 2000 census, San Ignacio/Santa Elena had a population of 13,545 people.