Background: Salvia officinalis (S. officinalis) has been vastly used in medicine as it possesses anticaries, antiplaque, anti-inflammatory, antibacterial, antifungal, antiviral, astringent, antioxidant effects. Aim: This study was executed to estimate the antibacterial effect of glass ionomer cement (GIC) containing S. officinalis on Streptococcus mutans (S. mutans) as main etiological factor of dental caries process. Methods: A total number of 12 specimens were assigned into 2 equal groups: Group 1(Control group) where conventional powder and liquid Fuji IX GIC was used and Group 2 (Test group) where the S. officinalis extract was prepared and added to the GIC liquid at 0.5% weight concentration level. Six disk shaped specimens, with diameter 10 mm and thickness 2 mm, were constructed for each group then tested, in vitro, against strains of S. mutans. Diameter of inhibition zone was recorded after 24 and 48 h. Results: During the study period, the mean diameter of the inhibition zones was high in the test group in contrast to the control group, with high statistically significant difference. Conclusions: Glass ionomer cement with S. officinalis extract has direct inhibitory effect towards S. mutans.