<p>Polystyrene nanoplastics combined with nano-silver in products like food packaging raise concerns about their interactions, which can significantly affect material properties within biological systems and may pose health risks to organisms. The purpose was to investigate the co-influence of polystyrene nanoparticles and nano-silver on testicular function in mice. Thirty-six mice were divided into 6 groups (Control, sham, 0.1 mg/day polystyrene nanoparticles, 0.5 mg/day polystyrene nanoparticles, 0.25 mg/kg/day nano-silver, and 0.1 mg/day polystyrene nanoparticles + 0.25 mg/kg/day nano-silver co-treatment). Groups were fed via gavage for 30 days. Sperm parameters analysis, testis histology analysis, testis weight measuring, testis biochemical assays including catalase activity, and malondialdehyde level were administered. Malondialdehyde level significantly increased in treated groups compared to sham except for 0.1 mg/day polystyrene nanoparticles. Malondialdehyde increased in co-treatment nano-silver + polystyrene nanoparticles compared to 0.1 mg/day polystyrene nanoparticle. Catalase activity decreased in treated groups compared to sham. Co-treatment nano-silver + polystyrene nanoparticles reduced catalase activity compared to the nano-silver. In treated groups, abnormal sperm count increased compared to the sham, while sperm count and motility decreased compared to the sham. Polystyrene nanoparticles, nano-silver, and their co-treatment reduced the numbers of spermatogonia, primary spermatocytes, and spermatids in seminiferous tubules compared to the sham. Testis weight increased slightly in nano-silver + polystyrene nanoparticles compared to the sham. Our findings showed that polystyrene nanoparticles disturbed the reproductive system’s function via the induction of oxidative stress. Moreover, it could reduce sperm quality, and nano-silver could intensify the damage caused by polystyrene nanoparticles in the testis.</p>