A comprehensive study of the correlation between the structural and morphological parameters and the frequency-temperature dependences of the conductivity of porous carbon materials obtained by carbonization of hemp fibers has been carried out. The effect of treatment with nitric acid and additional annealing on the transport of charge carriers in carbon materials carbonized in the temperature range of 500–1000 °C has been established. Porous carbon materials have been described as a heterophase system, in which highly conductive graphitized particles are separated by low conductivity amorphous carbon, from the standpoint of the effect of carbonization temperature and changes in the morphology of materials due to acid treatment and annealing on the formation of conduction channels with the simultaneous implementation of fluctuation-assisted tunneling between graphitic clusters separated by low conductive barriers and the formation of conduction channels as a result of contact of individual graphitized carbon clusters. A model has been constructed that relates the results of measuring the specific surface area and pore size distribution, changes in the size of graphite crystallites, and changes in conductivity with temperature. The possibility of applying the theory of percolation conductivity to describe the charge transport has been analyzed and the percolation threshold has been established.