The study investigates the antibacterial effects and mechanisms of zinc oxide (ZnO) nanoparticles against *Campylobacter jejuni*. ZnO nanoparticles were found to be highly effective in inhibiting and killing *C. jejuni*, with a minimum inhibitory concentration (MIC) of 0.05 to 0.025 mg/ml, significantly lower than that for *Salmonella enterica* serovar Enteritidis and *Escherichia coli* O157:H7. The nanoparticles caused a bactericidal effect, leading to the transformation of spiral-shaped *C. jejuni* cells into coccoid forms and increased membrane permeability. Gene expression analysis revealed upregulation of oxidative stress genes (*katA*, *ahpC*, and *dnaK*) by 52-, 7-, and 17-fold, respectively, indicating that the antibacterial mechanism is likely due to oxidative stress induction in *C. jejuni*. These findings suggest that ZnO nanoparticles could be a promising antimicrobial agent for controlling *C. jejuni* and other foodborne pathogens.The study investigates the antibacterial effects and mechanisms of zinc oxide (ZnO) nanoparticles against *Campylobacter jejuni*. ZnO nanoparticles were found to be highly effective in inhibiting and killing *C. jejuni*, with a minimum inhibitory concentration (MIC) of 0.05 to 0.025 mg/ml, significantly lower than that for *Salmonella enterica* serovar Enteritidis and *Escherichia coli* O157:H7. The nanoparticles caused a bactericidal effect, leading to the transformation of spiral-shaped *C. jejuni* cells into coccoid forms and increased membrane permeability. Gene expression analysis revealed upregulation of oxidative stress genes (*katA*, *ahpC*, and *dnaK*) by 52-, 7-, and 17-fold, respectively, indicating that the antibacterial mechanism is likely due to oxidative stress induction in *C. jejuni*. These findings suggest that ZnO nanoparticles could be a promising antimicrobial agent for controlling *C. jejuni* and other foodborne pathogens.