This thesis deals with the theme of declining moral values in Theodore Dreiser’s An American Tragedy (1925). My aim is to examine what led Clyde Griffiths, the protagonist of the novel to follow merely false principles like pursuing wealth and appearance in life. He is found guilty of the murder of his pregnant girlfriend, Roberta Alden. The question arises what drives him to commit a crime since his only aim is to realize his American Dream. To answer these questions I will explore the distortions in Clyde’s character caused by social expectations.