In this study, the sonocatalytic, photocatalytic, and sonophotocatalytic activity of chitosan-ZnSnO3 nanocomposites (CS-ZnSnO3 NCs) against crystal violet dye were investigated. By using a variety of contemporary techniques, the crystalline phase, purity, crystal structure, shape, elemental composition, particle size, thermal properties, functional groups, and optical absorption properties of the synthesized CS-ZnSnO3 NCs were studied. By examining the variation in dye absorbance under a UV spectrophotometer, the catalytic activity of CS-ZnSnO3 NCs on crystal violet dye has been observed. The degradation efficiency of crystal violet dye was found to be 43 %, 80 %, and 97 % for sonocatalytic, photocatalytic, and sonophotocatalytic activity of CS-ZnSnO3 NCs after 75 min, respectively. The effect of pH analysis demonstrates that maximum degradation is obtained at pH 10 and the reusability study reveals the stability of the CS-ZnSnO3 catalyst. The degradation of crystal violet dye follows the pseudo-first-order kinetics and the rate constant for the sonophotocatalysis is higher than the individual catalysis processes. The prepared CS-ZnSnO3 can be utilized as a sonophotocatalyst for the degradation of crystal violet dye in an environmental remediation procedure to treat wastewater.