Essential oils (EOs) have been used in the food industry, pharmaceuticals, and cosmetics since they are pure and have special aromatic qualities and are bactericidal, fungicidal, insecticidal, and have many other therapeutic advantages. Numerous studies have established nanoparticles (NPs) ability with wide spectrums, including antioxidants, anticancer and antimicrobial properties, for both EOs with metal/metal oxides NPs. The study aims to evaluate a dual combination therapy's antibacterial efficacy using Eucalyptus essential oil loaded on silica dioxide nanoparticles (SiNPs) against certain pathogenic bacteria. The antibacterial activity of the eucalyptus essential oil, SiNPs only, and its encapsulated form SiNPs against gram-positive (MRSA and S.aureus) and gram-negative bacteria (P.aeruginosa and E.coli) were investigated. The agar well diffusion method determined the antimicrobial activity of the eucalyptus EOs with and without SiNPs.Eucalyptus essential oil encapsulated with silica dioxide nanoparticles showed high antibacterial activity against MRSA, S. aureus, P. aeruginosa, and E. coli. In the present study, SiNPs only exhibited a significant increase in diameters of inhibition zones against S. aureus and MRSA compared to the eucalyptus essential oil. aeruginosa compared to the eucalyptus essential oil only. However, Eucalyptus essential oil loaded on silica dioxide nanoparticles revealed a significant increase of the diameters of inhibition zones against both gram-positive bacteria and gram-negative as compared to eucalyptus essential oil only and SiNPs only. The present study suggested that the potent efficacy of Eucalyptus oil against both gram-positive bacteria (MRSA and S. aureus) and gram-negative bacteria (P. aeruginosa and E. coli) could be improved by silica dioxide nanoparticles (SiNPs).