Social media is a Web 2.0 platform that allows to share content and information without the limitations of time and space. Social media networks have managed to become a part of today's lifestyle and are increasingly gaining importance when viewed from a state perspective. Sentiment analysis refers to the use of natural language processing, text analysis and computational linguistics to identify and extract subjective information in source materials. In this study, we focus on social media mining and sentiment analysis for students of an open and distance education system. Anadolu University which has approximately two million students and more than two million graduates, is a well-known institution in Turkey, that offers higher education through contemporary distance education model. Firstly, we have fetched Tweets related to Anadolu University open and distance education system. To perform sentiment analysis, these tweets were analysed by statistical and data mining techniques. Finally, results were visualized.