Knowledge extraction from online feedback system using ontology To achieve success in any teaching program it is very important to have adequate communication between teachers and students. Feedback given by student helps teachers to improve on performance and behavior. Semantic web (SW) technology is a promising approach for data selection and retrieval. Different web mining techniques are used for extracting useful information from web data. In this paper the main focus is to extract knowledge from the feedback given by the students and this can be done by firing Sparql Query in Ontology. This knowledge can be represented in meaningful form.