Klebsiella pneumoniae is one of common hospital-acquired bacteria causing nosocomial pneumonia, urinary tract infections, and intra-abdominal infections. The aim of this study is investigating the Modulation effect of Zinc Oxide nanoparticles (ZnO NPs) against multidrug resistant K. pneumonia which was isolated from Respiratory Tract Infections (RTIs). The results of isolation and characterization of bacterial specimens showed that 20.81% of RTIs were Klebsiella pneumoniae. The strongest isolate showed resistant for most usable antibiotics selected. Simultaneously, ZnO NPs were produced by an aqueous extract of Green Tea leaves as a reducing and stabilizer agent. The Ultraviolet-Visible (UV-Vis) spectrum was indicated a successful production of ZnO NPs at 383 nm. X-Ray Diffractometry (XRD) pattern showed peaks at 2θ positions matching to standards and indicating a formation of hexagonal (wurtzite) shape of ZnO NPs, with an average size of 22nm. Fourier Transform- Infrared (FT-IR) spectra of ZnO NPs revealed the participating of Green Tea biomolecules in the synthesis process. The minimum inhibitory concentration (MIC) of ZnO NPs against K. pneumoniae was 3.2 mg/mL. The results of using nanoparticles showed a morphological changing in K. pneumoniae colonies, and a modulation effect occurred against some antibiotic resistance of Klebsiella pneumoniae such as Gentamycin and Levofloxacin.