Santo Domingo Formation (Spanish: Formación Santo Domingo) is a mainly marine Miocene sedimentary formation located in south–central Chile.

[1][3] The formation was defined by R. Martínez Pardo and Mario Pino in 1979 and named after the roadcut locality they studied about 19 kilometres (12 mi) southeast of Valdivia.

[1] The sedimentary facies of the Santo Domingo Formation are composed of sandstone, siltstone, and mudstone with smaller amounts of conglomerate.

[2] Some of the trace fossils that can be found in the Santo Domingo Formation are Zoophycos isp., Chondrites isp., Phycoshiphon isp., Ophiomorpha isp.

[5] The most common formaineral species of the Santo Domingo Formation are Hansenisca altiformis, Rectuvigerina transversa, and Sphaeroidina bulloides.