The CoCe_xDy_xFe_2-2xO₄ (x = 0.0, 0.01, 0.02, 0.03, 0.04, 0.05) have been prepared by sol-gel auto-combustion technique. The structural result confirmed the formation of single phase cubic spinel structure showed by XRD. Crystallite size obtained from the XRD is in the range of 24–28 nm, whereas particle size obtained from the transmission electron microscopy is in the range of 20–30 nm. It is also found that the cation distribution of CoCe_xDy_xFe_2-2xO₄ resulted in the Fe³⁺ and Co ions occupy both tetrahedral A-site and octahedral B-site, whereas Ce and Dy cation distributed in both of them. The photoluminescence (PL) analysis reveals that all prepared samples contain four bands; (i) peak centered at 412 nm corresponding to ultraviolet (UV) band i.e. near band edge emission, (ii) a high intensity peak centered at 434 nm belonging to violet band, (iii) a low intensity and sharpness peak positioned at 466 nm refers to blue band, and (iv) a broad and very low intensity peak observed at 502 nm assigned to green band. FTIR results of the prepared samples showed that two vibration bands between 600 cm^–1 and 400 cm^–1 belonging to the stretching vibration of tetrahedral metal-oxygen bond (v_A) and stretching vibration of octahedral site (v_B) respectively. Mössbauer spectroscopy has also been performed to investigate the hyperfine structure of undoped, Ce and Dy co-doped cobalt nano ferrites. The higher values of M_S and H_hf for x = 0.01 composition can be attributed to the occupation of Dy³⁺ ions in octahedral site whereas the Ce³⁺ ions occupied to tetrahedral site.