The Oliní Group (Spanish: Grupo Oliní, K3k5o, K2ol, Kso) is a fossiliferous geological group of the VMM, VSM and the eastern flanks of the Central and western flanks of the Eastern Ranges of the Colombian Andes.

The regional group stretches from north to south across approximately 700 kilometres (430 mi) and dates to the Late Cretaceous period; Coniacian, Santonian and Campanian epochs, and has a maximum thickness of 287 metres (942 ft).

[8] The age has been estimated on the basis of ammonites to be ranging from Coniacian to Campanian.

[14] The Oliní Group was deposited in a relative high sea level environment in an outer platform setting,[15] following a sequence boundary, forming the base of the unit.

The radiolarites of the Upper Lydite Formation represent a maximum flooding surface.