The eighteenth century witnessed the development of an ideology of motherhood that promoted the notions that women are born to be mothers and naturally inclined toward childcare and domesticity. Throughout the century, in all manner of cultural forms, the mother’s role was constructed into a series of rules of maternal behaviour, sentiments, and responsibilities were promoted as the attributes of maternal excellence. Against the cultural imperative to define and idealize maternity, there emerged a body of fiction in which mothers and mother figures are deficient when measured against the exacting standards of maternal excellence. Either the mother fails because she does not exhibit the appropriate maternal sentiments that would propel her to perform the duties of the ideal mother, or she is absent and forced to leave the mothering of her child to others. These others – substitute mothers – are also deficient in some way. Whatever form deficient motherhood takes in these novels, the mother figure exerts some form of agency that affects the destiny of her child, and the outcome of the narrative. Through close textual analysis of the novels, Moll Flanders (1722), Roxana (1724), Clarissa (1747-9), Evelina (1778), and The Italian (1797), this thesis examines how literary representations of deficient motherhood are realized in English novels of the eighteenth century, and demonstrates why major writers, like Daniel Defoe, Samuel Richardson, Frances Burney, and Ann Radcliffe deployed this fascinating theme. It argues that there was a crucial change in the method of representation and that these two different methods were reflected by, and reflective of, the changing cultural and social requirements, needs, and desires to define and control motherhood. It further argues that the deficient mother was an effective narrative device for writers to explore the emerging ideas on gender and social class. The representative novels engage with issues pertinent to their historic time and place and highlight the extent to which mothers - and women in general – in eighteenth- century England were defined by the precepts of ideal motherhood, social class, and gender.