The paper presents results of phytosociological researches on rock faces vegetation of Pamir Alai Mountains. In total, 182 phytosociological relevés were made during the field studies conducted in 2006–2012, applaying the Braun-Blanquet method. Plant communities of calcareous firm rock faces and small fissures, inhabiting mainly the alpine and subnival zone in several ranges (e.g. Zeravshan Mts, Hissar Mts, Hazratishoh Mts, Darvaz Mts, Rushan Mts and Vanch Mts) are herein described for the first time. A hierarchical syntaxonomic synopsis of the rock communities of the Pamir Alai is provided. The collected vegetation samples represent the majority of the variability among the phytocoenoses of small crevices in limestone massifs in alpine and subnival zone. As a result of field research and numerical analyses, 14 associations have been distinguished: Sergietum regelii, Scutellarietum megalodontae, Scutellarietum rubromaculatae, Scutellarietum orbicularis, Campanuletum lehmannianae, Violetum majchurensis, Achoriphragmetum darvazici, Achoriphragmetum turkestanici, Asperuletum fedtschenkoi, Andrachnetum fedtschenkoi, Eritrichietum turkestanici, Minuartio litwinowii-Phaeonychietum surculosi, Silenetum kuhistanicae, Silenetum samarcandensis. Main factors determining the species composition of the classified associations seem to be the crevice type, the elevation above sea level and the availability of soil. Rocky habitats in Tajikistan, probably because of their high separateness and marginal position within the Irano-Turanian province, act as a refuge for many narrowly distributed plant taxa.