<p>This study presents the synthesis and comprehensive characterization of sustainable cobalt ferrite (CoFe₂O₄)/cellulose nanocomposites derived from palm date leaflets. Employing a co-precipitation method, magnetic nanoparticles were uniformly incorporated into a cellulose matrix at varying weight ratios. Structural analysis via XRD confirmed the successful integration of nanoparticles, with crystallinity influenced by the ferrite concentration. FT-IR spectra revealed strong interfacial interactions through hydrogen bonding between cellulose hydroxyl groups and ferrite surfaces. TEM revealed a uniform distribution of CoFe₂O₄ nanoparticles. Magnetic measurements revealed that variations in saturation magnetization values are generally attributed to changes in the ratio of ferrite nanoparticles. The thermal analysis reveals that cobalt ferrite nanoparticles improve thermal stability at lower ferrite contents and alter the degradation mechanisms of cellulose-based nanocomposites. At higher content, the more unbounded ferrite molecules could catalyze the cellulose decomposition, thus decreasing the thermal stability. The electrical studies revealed a shift in ac conductivity from insulator to semiconductor with increasing ferrite ratio, which may be attributed to changes in the conduction mechanism and the enhanced occurrence of ion hopping facilitated by iron ions (Fe²⁺/Fe³⁺). The results of this study confirm the feasibility of preparing cellulose/CoFe₂O₄ nanocomposites as multifunctional materials from sustainable and environmentally friendly sources.</p>