The chapter gives a brief account on occlusion and malocclusion. Occlusion is the relationship between the maxillary and mandibular teeth when they approach each other, during chewing or at rest. Malocclusion is the leading cause of a number of health and dental problems which is defined as the misalignment of teeth and jaws, or more simply a bad bite. Ideal occlusion is a state of relationship existing when all the teeth are perfectly in the arches of the jaws and they have a normal anatomic relationship to each other. Any tooth contacts made within the functional range, i.e. according to the size of the opposing tooth surfaces are called functional occlusion. A balanced occlusion is that which is in harmony with temporomandibular joints and the neuromuscular system. Other topics discussed are centric occlusion, classification of malocclusion, overjet and overbite.