Zinc substituted cobalt ferrite nanoparticles with elemental composition Co1−x$1-x$ZnxFe2O4 (x=0.0$x=0.0$, 0.2, 0.4, 0.6) were prepared by the sol-gel auto-combustion technique using Co, Fe, Zn nitrate as a precursor where nitrates to citrate was 1:3. The as prepared powder of cobalt zinc ferrite was sintered at 900∘C for 3$$h. Structural, morphological, dielectric and magnetic properties were studied by x-ray diffractometer (XRD), scanning electron microscope (SEM), high precision impedance analyzer and vibrating sample magnetometer (VSM), respectively. The peaks obtained from the XRD confirmed samples having crystallite (∼$\sim$32–36$$nm) single phase inverse spinel structure without any traceable impurity. Lattice parameters were calculated from XRD and it increases with Zn content. SEM revealed irregularly shaped grains (∼0.5$\sim 0.5$–0.7$$μ$\mu$m) morphology with heterogeneous distribution. The dielectric constant (ε′$\epsilon \prime$) and dielectric loss (tanδ$tan\delta$), have been measured as a function of frequency at room temperature. The dependence of ε′$\epsilon \prime$ and tanδ$tan\delta$ with frequency showed the normal dielectric behavior in accordance with the Maxwell-Wagner type of interfacial polarization and electron hopping change between Co2+$2+$ and Co3+$3+$ as well as between Fe2+$2+$ and Fe3+$3+$ ions at octahedral sites.