Medicinal plants have been used in traditional healthcare system in human history and are considered as a source of healthy human life. Different parts of the plants like roots, leaves, stem, bark, fruits and seeds have been used in fighting infection and strengthening the immune system. Murraya koenigii is a potential medicinal plant extremely valued for its characteristic aroma and bioactive compounds. In this study Murraya koenigii leaves extracts were screened for their In vitro antibacterial activity against streptococcus mutant by disc diffusion method in comparison with standard antibiotic streptomycin, penicillin, gentamycin and kanamycin. Streptococcus mutant commonly found in the human oral cavity, and is a major contributor of tooth decay. The ethanol, chloroform, methanol and hot water extracts of leafs of the plant were screened for phytochemical properties. Phytochemical screening study well showed the presence of carbohydrates, alkaloids, steroids, glycosides, protein, tannin, quinone, saponins and flavonoids in the leaf extracts of the plant. The hot water extract showed better antibacterial activity against streptococcus mutant. In silico study was carried out to screen the marker compounds from Murraya koenigii. Bismurrayafoline A and murrayazoin showed least binding energy with Streptococcus proteins.