The antibacterial effect of Moringa peregrina (leaves, roots and seeds) ethanolic extracts were investigated. The effect of plant extracts were tested against three bacterial species: Escherichia coli (E. coli ATCC25922), Staphylococcus aureus (S. aureus ATCC 43300) and Klebsiella pneumoniae (K. pneumoniae ATCC 13883). M. peregrina ethanolic extracts showed significant antibacterial effect on the three tested bacterial strains using the disc diffusion method. The inhibition zones caused by leaf ethanolic extracts were 14 to 30, 8 to 19 and 9 to 22 mm in diameter against E. coli, K. pneumonia, and S. aureus, respectively. Root ethanolic extracts showed inhibition zones as 18 to 42, 44 to 59 and 34 to 45 mm in diameter against E. coli, K. pneumonia, and S. aureus, respectively. Seed extract caused inhibitory zones of 16 to 38, 6 to 32 and 6 to 18 mm in diameter against E. coli, K. pneumonia and S. aureus, respectively. The results showed that the zones of inhibition for the three bacterial species increased in a dose dependant manner and that the M.peregrina root ethanolic extract exhibited more potent inhibition. The other test done to assess the antibacterial effect of M. peregrina ethanolic extracts was the minimum inhibitory concentrations (MIC). Such test was conducted on the same three bacterial species, where the MIC for the M. peregrina leaf extract for E. coli, K. pneumoniae, and S. aureus were 12.0, 15.0 and 18 mg/ml, respectively. The MIC for seed ethanolic extract was 13.0 and 7.0 mg/ml against E. coli, K. pneumoniae and S. aureus respectively. Also, the MIC for root ethanolic extract of M. peregrine against E. coli, K. pneumoniae and S. aureus was 9.0, 3, 2, and 5 mg/ml, respectively. Such low MIC values especially for the root extract represent strong potential for M. peregrina as an antibacterial agent.