The Tsagaantsav Formation, Tsagantsab Formation or Tsagan-Tsab Formation (Russian: Tsagaantsav Svita) is an Early Cretaceous (Hauterivian to Barremian) geologic formation in Mongolia.

[1] Indeterminate sauropod and psittacosaurid remains have been recovered from the formation.

[2] Remains of the pterosaur Noripterus, which were originally given their own genus, "Phobetor" have also been recovered from the formation.

[3][4] Graham et al. 2001 reported radiometric dates of 131 and 126 Ma from the formation.

[5] The following fossils were reported from the fluvial to lacustrine sandstones and siltstones of the formation:[1]