Cleft palate is the incomplete fusion of the palatine shelves in the mouth. This may be associated with problems in the formation of the primary (anterior) or secondary (posterior) palates.

Genetics has been implicated in cleft palate. Substance abuse or use of certain prescription drugs (e.g., Accutane) by the pregnant mother can also lead to diverse embryologic deformities in the newborn, such as cleft palate.