The Mesozoic succession of South Tibet, both in lithologies and stratigraphic thicknesses, compares much more closely with that of central Nepal than has been reported in the literature. Facies distribution, from relatively proximal environments in the south to more distal settings in the north, reflects the paleogeography of the Tethys Himalaya passive margin, representing the southern edge of Neotethys.As in central Nepal and NW Himalaya, accumulation rates increased greatly in the latest Triassic, when very thick shelfal siliciclastics and locally volcaniclastics (Tarap Formation) were followed by coastal sandstones (Zhamure Formation). Contrary to reports in the literature, this latter unit reaches well into the Liassic at least in proximal southern sectors. The base of the overlying Kioto Group, yielding rich faunal associations characterized by benthic foraminifers and Lithiotis, similar to those of western Tethys carbonate platforms, is dated as middle Liassic (most probably late Pliensbachian).The monotonous growth of carbonate ramps during the middle Liassic to early Dogger was interrupted by two siliciclastic episodes related to major paleogeographic changes in the Toarcian (middle part of the Kioto Group) and in the Bajocian–Bathonian (Laptal Formation). An early Callovian flooding event (Ferruginous Oolite Formation)—widespread all along the Tethys Himalaya—was locally followed by deposition of a markedly lenticular pelagic unit, previously reported only from the Thakkhola Graben (Dangar Formation). The overlying Spiti Shale is reduced to only 20 m in southern sectors, where it is not younger than the Oxfordian, whereas in northern sectors the unit is several tens of m thick and mainly ascribed to the Tithonian.Volcaniclastic deposition (Wölong Formation)—reported herein for the first time—probably began as early as the Kimmeridgian/early Tithonian and lasted until Aptian times, when it was replaced by sedimentation of relatively deep-water marlstones. This magmatic episode, related to tectonic extension associated with the detachment of India from Gondwanaland, took place earlier in South Tibet and progressively later in central Nepal and Northern India; as in Nepal volcanic products changed with time from predominantly basaltic composition to intermediate and bimodal character. The Early Cretaceous sedimentary evolution of South Tibet matches that of offshore NW Australia.