Photocatalysis has emerged as a promising technique for treating and removing various pollutants from wastewater. Its popularity is due to its environmental friendliness, as it requires only two main components: a photoactive catalyst, such as zinc oxide, and a light source. To enhance its environmental benefits, the green synthesis of zinc oxide is preferred. This study focused on producing zinc oxide nanocatalysts via green synthesis, using pullulan, a biopolymer, as the capping agent. The materials were synthesized using two fabrication techniques: sol-gel and precipitation. The resulting samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and surface area and pore analysis. The analyses indicated that zinc oxide nanocatalysts were successfully produced with high crystallinity, as evidenced by the narrow, high-intensity XRD peaks that corresponded well with the wurtzite crystal structure. Morphological analysis showed that the materials were nanosized, with average particle sizes ranging from 26 to 60 nm. The photocatalytic performance of the synthesized samples was evaluated through the photodegradation of anionic and cationic dyes, specifically methyl orange and rhodamine B, respectively. The highest degradation efficiency, 99%, was achieved for both dyes within 60 min. For methyl orange, the zinc oxide nanocatalyst produced via the sol-gel technique showed superior performance, while for rhodamine B, the nanocatalyst produced via the precipitation technique was more effective. These results demonstrate that green-synthesized zinc oxide nanocatalysts are highly effective at removing both anionic and cationic dyes from wastewater, with performance that can be optimized by selecting the appropriate fabrication technique.