At beginning of 2020, the world was shocked by the outbreak of the coronavirus from China. The coronavirus caused panic in China and killed thousands of Chinese people. Many people seemed to rely on social media for more information. As a result, social media platforms have become mediators between individuals and the rest of the world, even becoming the fastest-growing social applications. Among several well-known social media platforms, Twitter has gained special attention because users can easily broadcast information about their opinions on certain topics through public messages, called tweets. There was public anxiety about the Covid-19 vaccination. Public opinion and unrest are posted on Twitter. Based on this case, it is necessary to analyze the views or opinions of the public regarding the Covid-19 vaccination policy, especially regarding the Booster Vaccine type which can be categorized into positive or negative opinions circulating on Twitter. This research aims to analyze the views of the Indonesian people toward the Covid-19 Booster Vaccine using the K-Nearest Neighbor Algorithm (K-NN).