The structural, dielectric, and electrical transport properties of 30Na2O–20CaF2–(50–x)SiO2–xLu2O3 (x = 0–10 mol%) glasses were investigated for solid electrolyte applications. XRD confirmed the amorphous nature, while DSC, Raman, and PAL studies revealed enhanced network polymerization and rigidity of the glass network with increasing Lu2O3 due to Lu3 +–O–Si linkages. Dielectric permittivity, a.c. conductivity, were studied over 4 Hz–8 MHz and 306–633 K. Conductivity (both a.c and d.c.) decreased with increasing Lu2O3 concentration because of reduced ionic mobility. Electrical modulus and Cole–Cole analyses indicated dipolar relaxation associated with Ca2+–NBO complexes and Lu3+-induced structural distortions. Na+ ion hopping was identified as the dominant conduction mechanism with negligible polaronic contribution. Among all compositions, the glass containing 2.5 mol% Lu₂O₃ exhibited the highest ionic conductivity, indicating its potential as a solid electrolyte, with electrical transport predominantly governed by Na⁺ ion hopping and negligible polaronic contribution.