The Oca–Ancón Fault System (Spanish: Falla Oca-Ancón) is a complex of geological faults located in northeastern Colombia and northwestern Venezuela near the Caribbean Sea.

The fault system is of right-lateral strike-slip type and extends for an approximate length of 830 km (520 mi).

[2] The vertical to subvertical Oca fault segment in the western part of the fault system has a length of 265 kilometres (165 mi), running west–east through La Guajira, Colombia.

It forms the northern boundary of the Sierra Nevada de Santa Marta and cuts through the Serranía del Perijá continuing into Venezuela.

[1] Gómez Tapias, Jorge; Montes Ramírez, Nohora E.; Almanza Meléndez, María F.; Alcárcel Gutiérrez, Fernando A.; Madrid Montoya, César A.; Diederix, Hans (2015).