Research has suggested that perfectionism, agreeableness, and neuroticism may influence relationship adjustment; however, these personality variables have not been examined in conjunction when considering relationship adjustment. In a sample of 222 university students (95 male, 126 female), the perfectionism dimensions of concern over mistakes and parental criticism were found to be significantly negatively related to dyadic adjustment. Agreeableness and neuroticism were also significantly negatively related to dyadic adjustment, and accounted for significant variance in explaining dyadic adjustment, while perfectionism dimensions did not. The results suggest that while negative aspects of perfectionism, such as concern over mistakes, have an impact on dyadic adjustment, the personality variables of agreeableness and neuroticism have a more salient impact. The implications of these findings for research in interventions for perfectionism and relationship adjustment are discussed.