The temperature-concentration dependences of glass conductivity in the Na₂O-B₂O₃, Ag₂O-B₂O ₃, and Tl₂O-B₂O₃ systems are studied. The nature of charge carriers in glass of these systems is revealed experimentally and their dependence on the concentration is studied. Based on the methods of Hittorf, Tubandt, Hebb-Liang-Wagner, and also on the fulfillment of Faraday's Laws, it is shown that in glass of the Na₂O-B ₂O₃ system with [Na₂O] < 15 mol %, the protons take part in the transport of charge in addition to sodium ions. The unipolar sodium conduction is attained at [Na₂O] > 17 mol %. In glass of the Ag₂O-B₂O₃ system, the conduction is associated with the migration of both silver ions and protons. For Ag ₂O concentrations from 15 to 22.5 mol %, the transport numbers of silver ions vary in a range from 0.45 to 0.53 and are virtually independent of the Ag₂O content. In glass of the Tl₂O-B₂O ₃ system, the charge transfer is performed exclusively by protons. The contribution of the electronic component into the conductivity of glass in the systems studied does not exceed 0.01%. An interpretation of the temperature-concentration dependences of conductivity is put forward.