The personality traits of neuroticism and agreeableness are consistently related to marital quality, influencing the individual's own (i.e., actor effect) and the spouse's marital quality (i.e., partner effect). However, this research has almost exclusively relied on self-reports of personality, despite the fact that spouse ratings have been found to have incremental validity over self-reports for a variety of other important outcomes. In a study of 300 middle-aged and older married couples, we examined the incremental validity of spouse ratings of neuroticism and agreeableness in predicting concurrent levels of self-reported marital quality, observations of behavior during a marital disagreement task, and depressive symptoms. Neuroticism and agreeableness had expected actor and partner effects on each of these outcomes. Spouse ratings of these traits demonstrated incremental validity in estimates of actor and partner effects on marital quality, marital behavior, and depressive symptoms. Results suggest that spouse ratings of personality may be important additions to the typical reliance on self-reports for research and clinical assessment in marriage. (Contains 3 tables, 1 figure and 1 footnote.)