The Sabinal Formation is a Late Jurassic and Early Cretaceous-aged geological formation in Oaxaca, Mexico. It preserves a highly diverse marine fauna.
It was initially thought to only encompass the Late Jurassic (Kimmeridgian & Tithonian), but more recent studies have redefined it to cover the earliest Cretaceous (Berriasian & Valanginian) as well. It is part of the Tlaxiaco Basin, a prominent structural basin in southern Mexico that accumulated both continental and marine sediments between the Early Jurassic and the Paleogene. The most prolific site of the formation is the Kimmeridgian-aged Llano Yosobe site near Tlaxiaco.