<p>In this work, flexible carboxyl functionalized multiwalled carbon nanotube (f-MWCNTs)-based chitosan (CS)-PEG-CeO₂ composite films were prepared by the solution casting technique. The structural, thermal, morphological, dielectric, and electrical properties of the composites were investigated. The structural analysis confirmed the presence of CeO₂ and PEG inside the f-MWCNTs-CS composites by the XRD and FTIR spectra. The scanning electron micrograph shows that f-MWCNTs are distributed homogeneously with less porosity in the resultant CS matrix composite materials. The thermal stability of the CS-PEG-CeO₂-f-MWCNTs composites could be improved with the incorporation of filler contents. The CS-PEG-CeO₂-f-MWCNTs composite exhibited enhanced electrical properties compared to pure CS and CS-PEG-CeO₂ composites, obtaining an AC conductivity of 10⁻⁵ S/cm at 10²&#xa0;Hz, a dielectric loss of 3.4, and a dielectric constant of 403 with the addition of 10 wt% functionalized MWCNTs. Moreover, it is possible that the synergistic action of conductive f-MWCNTs and the incorporation of CeO₂ particles inside the CS and PEG matrix contributed to the enhancement of the dielectric and electrical performances of the composite films. The fabricated CS-PEG-CeO₂-f-MWCNTs composite films, developed through a simple and cost-effective method, exhibit enhanced dielectric and electrical properties, offering promising potential for application in next-generation electronic devices. </p>