With the beginning of the 19th century, England entered into a transitional period. Sociologists believe that in each era of transformation, the ruling class tries to establish its own values, but some resistance to these new values is inevitable. Thomas Hardy's novels in general, and Under the Greenwood Tree specifically, are no exception. Based on these notions, this paper tries to interpret Under the Greenwood Tree. Much of the criticism of Hardy's work insists on the point that the created characters in his work along with their new ideas emphasize Hardy's attempts in standing against the ideological discourses of the middle-class. Under the light of Althusser's theory of Ideological State Apparatuses (ISAs) and Antonio Gramsci's notion of hegemony, Hardy can be considered as a true subject of his society, one who tries to strengthen the pillars of his society through depicting characters who have to be in the mainstream of the current ideological discourses of his age. Therefore, dealing with various aspects of this novel, this study tries to see how Louis Althusser's notions can help us to understand Hardy himself, his characters as well as the era in which he lived and wrote.