The SW-Gissar range (westernmost part of the Tien Shan) consists of a succession of anticlines and synclines forming a relief between the Amu Darya and Afghan-Tajik basins. Recent fieldwork has been performed to study the development and the architecture of a vast Middle-Upper Jurassic carbonate platform. The studied carbonate series crops out along cliffs overlying Lower to Middle Jurassic continental then marine deposits. Carbonate thickness reaches 500 m in the central and southern Gissar and thins up northwards, near the paleo-border of the Amu Darya Basin. The goal of this study was to build a highresolution stratigraphic framework for these deposits, based on chemo-and lithostratigraphic correlations between seven sections. It was associated with a detailed microfacies analysis in order to establish the spatial and temporal evolution of the palaeoenvironments in this poorly known area. Two major sequences were recognized, (1) Callovian in age, and (2) possibly Oxfordian to Lower Tithonian. The reconstruction of the deposition profile indicates that the Gissar was a gently dipping ramp during the Callovian major sequence. Dark mudstones with entire bivalve and brachiopod shells and oncoids-rich float-to rudstones predominated below and around the storm wave base. Oobioclastic grainstones were deposited in the permanently agitated shallow water zone, while patch and pinnacle reefs built up distally at the inner-mid ramp transition and in the mid ramp. Small shallow water siliciclastic deltas developed close to the emerged lands located in the north. The Callovian sequence is subdivided into seven fourth-order transgressive-regressive sequences. The transition between the two major sequences is marked by a significant change in the carbonate sedimentary system associated with a positive shift in the bulk carbon isotope values. It could record a major climatic change coeval with the Middle-Late Jurassic Transition. Further, it is hypothesized that a sedimentary hiatus exists, possibly caused by the exposure of the platform. The Upper Jurassic major sequence is mostly composed of peritidal deposits, showing rapid vertical and lateral transitions, depicting a more complex architecture. The series consists in numerous meterthick alternations of pellets/algal pack-to grainstone, ‘microbial oncoid’ floatstone, ooid grainstones and mudstones. These deposits could have accumulated in a vast, mostly aggrading lagoon protected by a barrier reef. Basinwards, close to the Uzbek-Turkmen border, Middle Oxfordian organic-rich algal/microbial carbonates are intercalated within the platform carbonates and could have formed in small stratified and partly isolated intra-shelf depressions. Lastly, a general aridification of the basin could be responsible for the observed increase in gypsum characterizing the upper part of the carbonate platform (Late Oxfordian? to Tithonian?). The numerous oscillations in carbon isotopes evidenced in these evaporite-rich carbonates may be the consequence of high frequency exposure of the platform preceding the deposits of massive evaporite during the Tithonian. This study allows a better understanding of the paleoenvironmental evolution of the northern Tethys during the Middle and Upper Jurassic. Our results will be compared with other Peri-Tethyan Jurassic platforms in order to understand the carbonate platform response to large-scale climatic and tectonic changes occurring at this period.