Oral habits are learned patterns of muscle contraction and have a very complex nature. They are associated with anger, hunger, sleep, tooth eruption and fear. Basicallya habit is a routine of behavior that is repeated regularly and tends to occur unconsciously. Habits are one of the major etiologic factors which will leads to malformation in dento-facial structures. Habits are the most frequent cause of these malformations mostly seen in the early childhood and mixed dentition stages.The oral bad habits that cause malocclussion problems include:Thumb sucking, it is a normal habit for babies, but causes serious orthodontic problems if it continues long after the eruption of permanent teeth. Prolonged thumb sucking can create crowded, crooked teeth, or bite problems and speech problems. Lip-biting or fingernail biting, both habits can shift the teeth out of alignment. Tongue thrusting, some children thrust their tongue forward,pressing it against the lips with a force that can result in teeth malocclusions such as ‘open bite’ or teeth protrusion (overjet). Modern orthodontics are usually able to treat most teeth malocclusions successfully, but prevention can help the family to avoid the large cost of orthodontic treatment.