[en] ZnO was successfully synthesized using a simple precipitation method with zinc acetate dihydrate as the starting material and ammonium hydroxide solution as the oxidizer. Morphological analysis showed ZnO particle formation with a Zn/O atomic ratio of 0.75–0.92. The synthesized ZnO product was examined using X-ray diffraction measurement (XRD) with the corresponding major peaks implying a hexagonal wurtzite structure. The average crystal size was 18.26–20.49 nm and the specific surface area was 18.17–21.67 m²/g. The optical band gap was estimated in the range of 2.95–3.21 eV. For photocatalytic activity, the synthesized ZnO was dispersed in two kinds of organic dyes (eosin-Y and methyl orange) with an initial concentration of 10 mg/cm³. The activity was carried out under ultraviolet illumination and the absorbance was measured. The best degradation efficiency was observed with a maximum degradation rate constant of 6.75 × 10⁻³/min and 1.73 × 10⁻³/min for eosin-Y and methyl orange, respectively. The degradation efficiency exhibited a direct correlation to the SSA, with the high SSA provided by the nanostructure size exhibiting better degradation efficiency. Therefore, ZnO nanostructures synthesized from zinc acetate dihydrated using an ammonium hydroxide oxidizer was shown to be a potential material for photocatalytic activity. Graphical abstract: < Image>.