Zinc(II) oxide (ZnO) nanoparticles were easily produced in this research by thermal decomposition of the Zn(II) Schiff base complex. The ligand was synthesized via condensation of benzylamine with 2-hydroxybenzaldehyde. The Zn(II) Schiff base complex was prepared by the reaction between zinc salt and Schiff base with the molar ratio of 1:1 (metal:ligand). The binary complex powder was calcined at 700 °C to produce ZnO nanoparticles. Various methods were used to characterize the Schiff base, complexes, and nanoparticles, including 1H and 13C-NMR, FTIR, TGA, DTA thermal analysis, XRD, TEM, SEM, EDX, BET, UV-Vis Diffuse Reflectance, atomic absorption, melting point, and UV-Vis spectrophotometer. ZnO nanoparticles had an average crystallite size of 48.2 nm.