Leave Form Classification Using Naïve Bayes is a Classification system which uses supervised machine learning classifier i.e. Naïve Bayes classifier.Naïve Bayes Algorithm is a basic classification algorithm that uses keywords as features. It assumes every keyword on the document as independent entity, computes the conditional probability of each words and multiplies to get overall probability given a class. Leave Form is a document in which student write the reason they are on leave. The reason contains some fixed keywords like headache, out of valley which is our main target. This algorithm takes these words in account to classify the document. They calculate the individual probability of each word and finally put them in the class with the highest probability of occurrence.