The aim of the present study was to evaluate the anti bacterial activity of three essential oils Thyme, Peppermint and neem oil on Streptococcus mutans, the potent initiator and leading cause of dental caries world wide. Essential oils are distillates of the volatile compounds of a plant’s secondary metabolism and may act as phytoprotective agents. Their curative effect has been known since antiquity. It is based on a variety of pharmacological properties which are specific for each plant species. Antibacterial activity of the three essential oils, Thyme, Peppermint and neem oil were screened against Streptococcus mutans, using disc diffusion technique. The results of this study showed that the extracts at different concentrations exhibited anti bacterial activity against the bacterial species tested.