The Sepetiba Formation (Portuguese: Formacão Sepetiba) is a geological formation of the Santos Basin offshore of the Brazilian states of Rio de Janeiro, São Paulo, Paraná and Santa Catarina.

The predominantly coquina formation dates to the Pleistocene period to recent and has a variable but maximum thickness of 570 metres (1,870 ft).

The formation is named after Sepetiba, a neighbourhood of Rio de Janeiro.

It has a variable thickness, with a maximum of 570 metres (1,870 ft),[1] due to the proximal erosion of the uppermost part.

The formation consists of whitish grey fine to coarse grained carbonitic sands.