Oral habits are commonly seen during normal development .They are acquired during infancy or may begin in childhood. They usually result due to lack of harmony between child and his environment. Some habits have a psychological origin and some result due to abnormal facial growth or are simply acquired by imitation and may infuse a sense of comfort to the child. Oral habits include but may not be limited to digit sucking, mentalis habits, postural habits, abnormal swallowing and oral self mutilation if they persist beyond the preschool age lead to the development of malocclusion . Repetitive or stereotype behaviours are common during childhood. Biological and environmental factors are important in causing and maintaining these behaviours most of which are benign and self limiting. Prevention and early interception is of great value in reducing the malocclusion from perpetuating further. This book explains various oral habits in a very concise manner and will be really helpful to dental health care professionals.