Resentment is a personal and social phenomenon illustrated widely in John Osborne's masterpiece, Look Back in Anger. The central idea of Osborne's illustration of this phenomenon is to present the dissatisfaction of the English individual with the political, economic and the religious situation of the time. The study deals with the term, resentment and how it is presented through the major characters so as to concentrate on the main issues discussed in the play. The study consists of three sections and a conclusion. The first section introduces the term, resentment. It investigates its origin and definition with the intention of presenting a vivid picture of the term in particular and the events of the play in general. The second section is mainly concerned with John Osborne as a member of The Young Angry Men and his life which have a great impact on his literary career. Young Angry Men is a group of British playwrights who appeared during the 1950s and 1960s. This section also presents the playwrights' ideas of the current circumstances of the period that are presented in their dramatic works. The third section discusses resentment as a personal and social phenomenon in Osborne's Look Back in Anger. It shows how resentment is employed through the major characters of the play, especially Jimmy Porter over the society and the formal institutions in the play after being left wrecked and desolate in the period following the World War II. Finally, the conclusion sums up the results inferred from the investigation of resentment in the study.