Abstract: The first principles calculations of single-wall and double-walled nanotubes have been performed. The nanotubes have been formed by rolling up binary MX and mixed (Janus) M ₂XY (M = Ga, In; X, Y= S, Te, X ≠ Y) monolayers. The structure and stability of nanotubes with two types of chirality and different diameters have been investigated. The modeling of double-walled nanotubes based on post-transition metal chalcogenides has been performed for the first time. The nanotubes stability has been analyzed with respect to the monolayers and with respect to the stable phases of bulk crystals. The role of binding energy to increase the stability of Janus double-walled nanotubes in comparison with that of binary double-walled nanotubes is discussed.