Writing about emotional experiences is associated with a host of positive outcomes. This study extended the expressive-writing paradigm to the realm of romantic relationships to examine the social effects of writing. For 3 consecutive days, one person from each of 86 dating couples either wrote about his or her deepest thoughts and feelings about the relationship or wrote about his or her daily activities. In the days before and after writing, instant messages were collected from the couples. Participants who wrote about their relationship were significantly more likely to still be dating their romantic partners 3 months later. Linguistic analyses of the instant messages revealed that participants and their partners used significantly more positive and negative emotion words in the days following the expressive-writing manipulation if the participants had written about their relationship than if they had written about their daily activities. Increases in positive emotion words partially mediated the relation between expressive writing and relationship stability.