Reaction time (RT) is the measure of how rapid the person responds to the given stimulus. Most of the literatures have used RT as one of the outcome measure in training neurologically intact children and adults to achieve excellence. Here we present the detailed narrative review about RT from various databases such as PubMed, ProQuest, OvidSP and EBSCO. From critical analysis of this narrative review, it is found that there is dearth in literature lacking the reference standards of RT among them.