DERLIAN MBENGO. The Fanaticism of The Main Character in Novel “Fangirl” by Rainbow Rowell: A Sociological Approach (Supervised by Novi Rusnarty Usu, S.Pd, M.A and Rusni Podungge, S.Pd, M.A) This research aims to discuss the fanaticism shown by a fandom towards the environment and the people around it in the novel Fangirl by Rainbow Rowell. The research analyzed fanaticism behavior and the impact it has on life and the people around it due to the influence of fandom. Not only that, social facts that are related to the influence of fandom on life and the people around them are examined. This study uses the approach of 'literature as documentation of social interaction' which is explained in the theory of the sociology of literature by Alan Swingewood (1972) and the theory of fandom put forward by Jenkins (1992). In addition, the researcher analyzes the data collected from the objects using qualitative techniques. The main data source comes from the novel Fangirl by Rainbow Rowell. Based on the analysis of the data shown in the novel, fandom influences fanaticism to foster excessive enthusiasm and loyalty, and aggressive behavior. In addition, there are many impacts caused by the influence of fanaticism on life and the people around the fandom. Keywords: fangirl novel, fanaticism, sociology of literature