Transparent 3Na2O–6.5B2O3 (NBO) glasses were fabricated via the conventional melt-quenching technique. X-ray powder diffraction (XRD) combined with Differential Scanning Calorimetric (DSC) studies carried out on the as-quenched samples confirmed their amorphous and glassy nature, respectively. The frequency and temperature dependent of the dielectric constant, electric modulus and electrical conductivity of the transparent NBO glasses were investigated in the 100 Hz–10 MHz frequency range. The electrical modulus and conductivity data have been rationalized using Jonscher's universal law. The bulk dc conductivity at various temperatures was extracted from the electrical relaxation data. The activation energy associated with dc conductivity is 0.52 ± 0.01eV, which is ascribed to the motion of Na+ ions in the glass matrix.