In this modern age, 21st-century people are attracted more towards the outside oily and calories rich junk food than homemade healthy food. Especially this group includes children and youth. Either due to the taste of tongue or due to circumstances like hostel life, they are attracted to these unhealthy fast or junk food. These junk foods are bad for physical health and especially for oral health. Under this topic, we shall discuss the influence of junk food in dental caries which is increasing day by day especially in children and young people due to their modern lifestyle.