A series of nanocrystalline lanthanum-substituted manganese ferrite having compositional formula MnLaxFe2−xO4 (x = 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a chemical co-precipitation method. Phase analysis was carried out using XRD. It reveals the formation of spinel phase without any unwanted secondary phases. The formation of single-phase spinel structure was supported by FTIR studies. Microstructural study was carried out using SEM. Elemental composition was studied using EDX. Electrical properties namely frequency variation of dielectric constant, dielectric loss tangent, and ac conductivity of prepared nanoferrites were studied. The observed electrical properties were discussed and explained in terms of hopping mechanism of charge carrier in ferrites.