The structural, elastic, electronic, thermodynamic, and phonon properties of TmSb which crystallizes in NaCl (B1) phase were analyzed by performing ab-initio calculations based on density functional theory using the Vienna Ab-initio Simulation Package (VASP). The exchange correlation potential within the generalized-gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) was used. The calculated structural parameters, such as the lattice constant, bulk modulus and its pressure derivative, cohesive energy, and second-order elastic constants are presented for B1 and CsCl (B2). This compound exhibits crystallographic phase transition from the B1 to B2 structure at pressure 29.13 GPa. In order to gain further information, for B1 phase, we investigated the elastic properties such as, Zener anisotropy factor, Poisson's ratio, Young's modulus, and shear modulus; the thermodynamic properties such as, the pressure and temperature dependent behavior of the normalized volume, bulk modulus, heat capacity, thermal expansion coefficient, Debye temperature, Gruneisen parameter, and entropy over a pressure range of 0-18 GPa and a temperature range of 0-1000 K. The electronic band structure, total density of states, phonon dispersion curves and one-phonon density of states of B1 phase are also presented. The obtained results are compared with the available experimental and theoretical data. (C) 2011 Elsevier Masson SAS. All rights reserved.