This experimental study was carried out to determine the antibacterial effect of Ethanolic extract of Aloe vera leaf gel (EAE) against standard strains of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae in the Department of Pharmacology & Therapeutics in collaboration with the Department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh from July 2017 to June 2018. Ethanol extract was used in five different concentrations (100, 200, 300, 400 and 500μg/ml). Dose dependent inhibitory effect was seen against the test organisms using disc diffusion method. For S. aureus, Zones of inhibition (ZOI) were 7, 12, 13, 16 and 20 mm at 100, 200, 300, 400 and 500 μg/ml respectively; for P. aeruginosa, ZOI were 0, 7, 12, 14 and 17 mm at 100, 200, 300, 400 and 500 μg/ml respectively; for E. coli, ZOI were 0, 8, 12, 15 and 18 mm at 100, 200, 300, 400 and 500 μg/ml respectively; for K. pneumoniae, ZOI were 7, 10, 11, 13 and 17 mm at 100, 200, 300, 400 and 500 μg/ml respectively. The minimum inhibitory concentration (MIC) was assessed by broth dilution technique. The MICs of EAE for S. aureus, P. aeruginosa, E. coli and K. pneumoniae were 500, 650, 650 and 600 μg/ml respectively. From the study it is clearly observed that ethanolic extract of Aloe vera leaf gel possesses antibacterial effect against the test pathogens. Further studies are required to detect and isolate the biologically active ingredients present in the Aloe vera leaves which are responsible for this antibacterial effect. Hopefully, that would lead to the discovery of new and more potent antimicrobial agents originated from Aloe vera.