In this study, Langmuir-Blodgett (LB) films were prepared with the compounds having long alkyl tails, and their tribological behaviors were investigated. The frictional forces were measured with lateral-force microscope (LFM), and they were discussed as a function of chain length, scanning rate and loading force. . The LB films gave maximum friction at a specific scan rate. For example, the LB film of poly(tetradecyl acrylate) showed maximum friction force when it deformed with probe tip at 8–12 µm/s. The LB film having longer alkyl tails, e.g. poly(octadecyl acrylate), showed maximum friction at slower scan rate. Deceleration of the scan rate showed an equivalent effect with shortening the chain length. In the phase transition of the Langmuir monolayer, equivalence was reported between temperature and the number of carbon in the alkyl tail. The phase transition temperature increased with the elongation of alkyl chain. These results show that there is some equivalence between shear deformation rate and chain length on the friction of the organic ultrathin films, which was similar to the time-temperature equivalence in the viscoelastic deformation of polymers. The scanning rate at frictional maximum, νSR,max, was expressed as follows, log(nSR,max(n))=log(nSR,max(n+m)×aCLm) where n and m are number of carbon atoms in alkyl chain, aCL is a shift factor. The equation supports that the energy dissipation at the phase transition causes the frictional shift with chain length for the ultrathin films.