The housefly, Musca domestica Linnaeus (Diptera: Muscidae), is an important pest not only causing annoying to humans but is also known for its ability to transmit different infectious microorganisms to humans and animals. Recently, zinc oxide nanoparticles (ZnONPs) synthesized by microbial organisms have gained much attention in pest control because of their extensive antimicrobial activity, eco-friendliness, and simplicity. Therefore, the green synthesis of ZnO nanoparticles was applied in the current study as a new and effective biopesticide against the house fly, Musca domestica by feeding the first instar larvae on different concentrations of ZnONPs synthesized by Bacillus foraminis (0.01, 0.025, 0.05, 0.1, 0.25, and 0.5 mg). Results showed significant mortality values in the larval stage (1.84 ± 0.10, 3.50 ± 0.29, 5.75 ± 0.25, 7 ± 0.41, 8 ± 0.41 and 8.75 ± 0.25) while pupae recorded mortality values of (1.75 ± 0.14, 1 ± 0.00, 1.63 ± 0.13 and 1 ± 0.00) at the higher concentrations (0.05, 0.1, 0.25, 0.5 mg), respectively and some morphological changes appeared in some pupae. Also, the adult emergence had a significant reduction (100 ± 0.00, 82.5 ± 2.50, 62.5 ± 4.79, 37.5 ± 2.50, 28.35 ± 0.95, 17 ± 0.08 and 0 ± 0.00), in comparison with the control group C (10 ± 0.00). ZnONPs showed effectiveness against M. domestica, suggesting it as a new and promising method in pest control.