Teeth are excellent hard tissues for anthropological, genetic, odontological, and forensic investigations, in both living and non-living populations. Their hardness makes them more resistant to high temperatures and bacterial decomposition. Among all teeth, mandibular canines exhibit the greatest sexual dimorphism. Determining sex from the morphology of mandibular canine teeth may be a valuable method, especially in mass disasters such as hurricanes or conflagrations. This study was conducted on 60 South Indian subjects, 30 males and 30 females aged 17-21 years, to establish the effectiveness of mandibular canine measurements in determining an individual's sex. An accuracy rate of 78.3% was observed, indicating statistically significant sexual dimorphism in the mandibular canine, which can be considered the "key teeth" for sex determination.