Owing to its realistic expression of issues, a social novel is able to reflect the realities of society better than other genres. The novel "Mama Hessa's Mice" shows the Kuwaiti society issues realistically. Sectarianism is the central theme of the events in the story. Through the analytical descriptive method, this research describes the literary and social structures of this novel and its role in the reflection of the social realities. The social structure of the novel is composed of different groups, and the type of their interaction has led to sectarian behavior from insult to ridicule and violence. The misunderstanding of ideas, addressing superstitions and blind imitation are the causes of these behaviors in this novel. Mutual respect, acceptance of others, turning to true Islam, avoiding extremism and patriotism are the solutions to this problem. The literary structure of this novel helps to cultivate the theme through unbiased narration, different points of views, child narrators and intertextual relationships.