This study was concerned with the effects of mechanical activation (MA) on structural characterization for neutral leach residue of zinc calcine (NLR) and kinetics of indium extraction from NLR in sulphuric acid. The X-ray diffraction (XRD) analysis showed that MA caused the decrease in crystalline phase and increase in lattice distortion. The activation time, reaction temperature and H2SO4 concentration had positive effect on indium extraction from NLR. The activation energies of the unactivated, milled for 30 and 60 min NLR samples calculated for indium extraction were 39.3, 32.1, and 30.4 kJ/mol, respectively, which indicated that MA increased the leaching kinetics of indium extraction from NLR. The empirical orders of the unactivated, activated for 30 and 60 min samples for extracting indium with respect to H2SO4 concentration were 0.52, 0.51, and 0.51, respectively.