This study assesses the mechanical, thermal, and dielectric properties, as well as the conductivity and water contact angle, of eco‐friendly polyethylene oxide (PEO) and aluminium oxyhydroxide (AlOOH) films prepared using water as a green solvent for fabricating flexible nanodielectric devices. X‐ray diffraction and Fourier transform infrared analysis confirm the presence of AlOOH in the nanocomposites. Field emission scanning electron microscopy analysis reveals the surface morphology of nanocomposites, showing a more uniform distribution of AlOOH nanoparticles at 5 and 7 wt% loading. The influence of nanofiller content on the thermal properties of films is evaluated by differential scanning calorimetry and thermogravimetric analysis. Increasing AlOOH content significantly enhances both the glass transition temperature and the thermal stability of PEO/AlOOH nanocomposites. The films exhibit improved mechanical properties, with a tensile strength of 31.11 MPa and Young's modulus of 339 MPa at 5 wt% AlOOH. Electrical conductivity, dielectric parameters, and complex impedance are measured for all films. The PEO with 7 wt% AlOOH shows optimal electrical conductivity and dielectric constant. These findings suggest that altering AlOOH concentrations enables fine‐tuning of the thermal, mechanical, and electrical properties of nanocomposite films. This versatility offers great potential for developing advanced flexible organoelectronic devices and nanodielectric materials.