We examined age-related changes in emotional behavior in a sample of middle-aged and older long-term married couples over a 13-year period. Data were collected at 3 waves, each occurring 5 to 6 years apart. For the present study, only couples who participated in all 3 waves were examined (n = 87). Couples were either in the middle-aged group (40-50 years old, married at least 15 years) or the older group (60-70 years old, married at least 35 years). At each wave, couples engaged in 15-min unrehearsed conversations about an area of disagreement in their marriage. Emotional behaviors during the conversation were objectively coded using the Specific Affect Coding System. Latent growth curve analyses revealed that, for both husbands and wives, negative emotional behavior (primarily belligerence, defensiveness, fear/tension, and whining) decreased and positive emotional behavior (primarily humor, enthusiasm, and validation) increased with age. Findings generalized across middle-aged and older cohorts and levels of marital satisfaction. These findings support theories that suggest that positive emotion increases and negative emotion decreases with age, expanding upon previous findings by examining objectively coded emotional behaviors longitudinally in an interpersonal context. (PsycINFO Database Record (c) 2020 APA, all rights reserved).