Context: Dental caries, a ubiquitous multifactorial infectious disease, is primarily caused by microorganisms like Streptococcus mutans and Lactobacillus acidophilus. Use of antimicrobials is an important strategy to curb cariogenic microorganisms. Aim: The aim was to evaluate the in vitro antimicrobial activity of C. sinensis extract on S. mutans and L. acidophilus. Study Setting and Design: Experimental design, in vitro study, lab setting. Materials and Methods: Aqueous, acetone and ethanolic extracts of C. sinensis were subjected to antioxidant analysis. The ethanolic extract was used for assessment of antimicrobial properties. Ethanolic green tea extract at ten different concentrations and 0.2% chlorhexidine was used. Microbiological investigations were carried out to determine the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and zone of Inhibition of the test and control agents against S. mutans and L. acidophilus. Statistical Analysis: Kruskall–Wallis and Mann–Whitney Uâtest. Results: MIC of green tea extract on S. mutans and L. acidophilus was found to be 0.2% and 0.3% respectively, MBC was found to be 0.8% and 0.9%, respectively. The mean zone of inhibition for 30 μl containing 300 μg of ethanolic extract of green tea and control against S. mutans were 18.33 mm and 14.67 mm, respectively. The mean zone of inhibition for 30 μl containing 300 μg of ethanolic extract of green tea and control against L. acidophilus were 12.67 mm and 7.33 mm, respectively. Conclusion: Green tea has antibacterial activity against predominant cariogenic bacteria namely S. mutans and L. acidophilus.