Zinc oxide nanoparticles (ZnO-NPs) were synthesized using a green eco frindly solution combustion route, employing zinc nitrate hexahydrate as the oxidizer and gum Arabic as a bio-organic fuel. No other chemical reagents were added during the synthesis process. The synthesized ZnO-NPs were characterized for average crystallite size, morphology, porosity, some of obtical properties and selected mechanical parameters. XRD analysis confirmed a single-phase hexagonal wurtzite structure, with an average crystallite size of ~14 nm as determined from the Size–Strain Plot (SSP) model, which provided the most consistent results among Debye–Scherrer, Williamson–Hall, and Halder–Wagner models. The average crystallite size, energy density value, micro strain and internal stress were estimated from peak broadening analysis. SEM images revealed a highly porous morphology with an average pore diameter of ~784 nm, implying a high specific surface area calculated from pore distribution analysis. UV–VIS spectroscopy exhibited a sharp excitonic absorption peak around 368.4 nm corresponding to a direct optical band gap of 3.8 eV. Fourier transform infrared spectroscopy (FTIR) confirmed ZnO stretching vibrations between 500–700 cm⁻¹, verifying ZnO formation. Compared with previous literature, this synthesis route offers a sustainable, low-cost, and purely plant-based alternative that yields nanosized ZnO with enhanced surface area and controlled microstructure, suitable for photocatalytic and optoelectronic applications.