This thesis investigates the prejudices in Geoffrey Chaucer‘s The Canterbury Tales. There are thirty pilgrims and twenty-two tales in this grand work. As it is unlikely to discuss all of them in one thesis, I focus my research on four pilgrims—the Miller, the Prioress, the Wife of Bath, and the Pardoner—to demonstrate Chaucer‘s prejudices in various aspects. The chapter on the Miller analyzes how men and women interact in sexual terms in the public domains and private spaces, investigating the poet‘s sexual discrimination in his final distribution of punishments for the characters as well as his chauvinistic disregard of the female body and its autonomy; Chaucer‘s punishment is not entirely of 'poetic justice' as it is dispensed at the cost of class victimization and the vilification of the female body. The Prioress‘s chapter discusses the poet‘s prejudices against female religious, exploring how Chaucer is affected by conventional descriptions of courtly ladies and contemporary conception of female religious‘ sexuality when he contradictorily glosses the Prioress as a romantic beauty; Chaucer‘s language prejudice and his innuendo of the Prioress‘s sexual attraction reflect his contempt and mis-evaluation of the Prioress‘s status, social function, and professional abilities. The chapter on the Wife of Bath examines 'The Wife of Bath‘s Prologue' as a manifestation of a medieval woman‘s life education, demonstrating how Alisoun is molded by mercantile marriage transactions, the tradition of misogyny, and the auctoritees‘ ill-meant religious instruction through garbled texts; the Wife‘s deafness does not signify her resistance or inability to understand men‘s 'truth', but an undeserved punishment from her frustrated educators. The Pardoner‘s chapter examines the Pardoner as a feminized and marginalized figure, exhibiting the narrator‘s, the Host‘s, and the Canterbury pilgrims‘ fear and hate of the 'different', the 'perverse', and the non-heterosexual; the Pardoner is treated as 'Other' of the Canterbury group and is brutally 'Othered' by the pilgrims despite his efforts in heterosexual identity and conformity. My study of Chaucer‘s prejudices will naturally extend to the investigations of modern readers‘ prejudices, particularly critics‘ false interpretation of the Miller‘s Alisoun‘s 'escape', denial of the Prioress‘s beauty, misconception of Jankyn‘s violence, and unconscious siding with patriarchy in the 'Othering' of the Pardoner, among others.