People often modify their emotional responses through the process of emotion regulation (Gross, 1998) for hedonic or instrumental goals (Tamir, 2016). However, these emotion regulation processes can differ based on: (1) whether the emotions are based on one’s group membership (i.e., group-based) or not (i.e., individual-based), and (2) whether another person is involved in this emotion regulation process (i.e., interpersonal) or not (i.e., intrapersonal). Less research has examined how group-based emotions are regulated with others, particularly how group members influence others’ emotions. Over three studies, this dissertation tested a model in which group members attempt to regulate the emotions of ingroup and outgroup members to achieve group goals (Hypothesis 1). In this model, emotions are perceived as instrumental to group goals (or not) based on whether the target is an ingroup or outgroup member (Hypothesis 2). Group members attempt to upregulate instrumental emotions and downregulate non-instrumental emotions for ingroup members, and downregulate instrumental emotions and upregulate non-instrumental emotions for outgroup members (Hypothesis 3). These regulation attempts then result in greater upregulated emotions in ingroup rather than outgroup members (Hypothesis 4). Study 1 experimentally manipulated the group membership of the target to examine whether group members regulate the emotions of ingroup and outgroup members that are instrumental in achieving ingroup goals. The results showed that regardless of the valence of the emotion (i.e., the emotions of happiness and anger), group members attempted to upregulate instrumental emotions and downregulate non-instrumental emotions for ingroup members, and downregulate instrumental emotions and upregulate non-instrumental emotions for outgroup members. Study 2 used archival data to test whether more liberal or more conservative media sources try to influence the emotions of their readers (i.e., ingroup members) about politically group-relevant (i.e., COVID-19 and Ebola) but not politically group-irrelevant events (i.e., celebrity deaths). Results showed that the political identity of media sources influenced how they tried to regulate the instrumental emotions of their readers. More liberal media sources were more likely than more conservative media sources to try to upregulate anxiety (but not other emotions) due to its instrumentality for the politically group-relevant event of COVID-19. Study 3 extended Study 2 to determine whether the regulator’s emotion regulation attempts resulted in the experience of greater upregulated anxiety in ingroup rather than outgroup members (that is, whether ingroup members were more affected by ingroup regulators’ attempts to change their emotions than were outgroup members). However, results indicated that the emotions that the regulators were trying to influence were experienced by both ingroup and outgroup members. Together, these studies suggest that group members attempt to regulate the emotions of ingroup and outgroup members based on the instrumentality of the emotion to group goals, influencing the target's emotions.