Perfectionistic traits have been associated with stronger weight and diet concerns. Maladaptive perfectionism is tied to critical evaluation tendencies such as excessive concern about making mistakes, increasing one's risk for eating disorder pathology. Knowledge about healthy diet and nutrition may be one factor influencing associations between perfectionistic tendencies, as individuals with eating disorders may be more attuned to sources of nutrients. The current study examined whether nutrition knowledge moderates the association between one facet of perfectionism, concern over mistakes, and shape/weight concerns and the association between concern over mistakes and global eating pathology. College women (N = 122) completed questionnaires on disordered eating attitudes, nutrition knowledge, and perfectionism. Concern over mistakes was positively related to shape/weight concerns and global eating pathology. Nutrition knowledge significantly moderated the association between concerns over mistakes and shape/weight concerns, such that the association was stronger among those with higher levels of nutrition knowledge. Furthermore, nutrition knowledge displayed trend-level significance for the moderation of the association between concern over mistakes and global eating pathology. College women displaying high levels of concern over mistakes who are more informed about nutrition knowledge may be more vulnerable to developing concerns about body shape/weight and eating disorder pathology.