Apart from being used for the treatment of malaria fevers, mono-herbal preparation of Ugandan Phyllanthus amarus is widely by local communities in central Uganda, for treatment of bacterial dysentery.  However, efficacy studies regarding the mono-herbal extracts of the Ugandan Phyllanthus amarus against Shigella dysenteriae is lacking. The present study was aimed at determined the antibacterial activity of aqueous ethanol crude extracts of whole plant of Phyllanthus amarus against Shigella dysenteriae. Whole plant of Phyllanthus amarus was collected from Wakiso district central of Uganda. Different concentrations (128µg/ml, 256µg/mL-1 and 512µg/ mL-1) of the ethanol crude extract of whole plant of Phyllanthus amarus were tested against Shigella dysenteriae using agar well diffusion method. Minimum inhibitory concentration (MIC) was determined using broth tube dilution method while Minimum bactericidal concentration (MBC) was determined by culture method. The results of this study showed that, Shigella dysenteriae was sensitive to different concentrations (128µg/ mL-1, 256µg/ mL-1and 512µg/ mL-1) of ethanol crude extract of whole plant of Phyllanthus amarus possessed antibacterial against Shigella dysenteriae with mean and standard error mean zone of inhibition ranging from 11.5±0.5 to 13.5±0.5mm, while the positive control had mean and standard error mean zone of inhibition 24.5±0.5mm. The MIC and MBC of the ethanol crude extract of whole plant of Phyllanthus amarus against Shigella dysenteriae was found to be 32µg/ml and 64µg/ml respectively. This study found that the whole plant of phyllanthus amarus of ethanol crude extract was active against Shigella dysenterie.  Further study should be carried out test whole plant Phyllanthus amarus crude extract on different microorganisms that cause dysentery to find out its activity against them and spectrum, determine lead compound in the whole plant Phyllanthus amarus crude extract responsible for the anti-microbial activity against Shigella dysenteriae and also determine the mechanism of action by which this plant crude extract inhibits Shigella dysenteriae.