Most emotion regulation research investigates how individuals manage their own emotions but in everyday life, emotion regulation often takes place in an interpersonal context-that is, through the intervention of others, especially close relationship partners. In this manuscript, we describe a 2-week daily diary study of 197 couples, in which we examined the nature and effectiveness of partners' attempts at interpersonal emotion regulation. Organized around the extended process model of emotion regulation (Gross, 2015), we examined the frequency and perceived effectiveness of six strategies for regulating negative emotions and two strategies for regulating positive emotions, as well as the impact of emotional regulation effectiveness on relationship satisfaction. Results indicated that situation modification was the most common approach to regulating negative emotions, whereas savoring was most common for positive emotions. Most strategies were perceived to be effective by both regulators and their targets, with the exception of suppression for negative emotion, for which evidence was mixed, and dampening for positive emotion, which was not viewed as effective. The influence of emotion regulation on relationship satisfaction depended on one's perspective: Regulators felt that their effective efforts benefitted their relationships, but even when targets experienced emotion regulation as effective, they indicated no improvements in relationship satisfaction, perhaps because the emotion-eliciting events were still salient to them. Broadly speaking, this research highlights the value of examining emotion regulation in an interpersonal context, and in the context of partners' ordinary, everyday social interaction. (PsycInfo Database Record (c) 2023 APA, all rights reserved).