This dissertation investigates the ways people perceive prosocial behaviors when enacted by an outgroup (vs. ingroup) member. Specifically, it focuses on the moderating and/or influential role of several personal and social factors that might shape such perception. To further elaborate the overall aim of this dissertation, I suggest that those in need, or those who observe an ingroup member in need, attribute less empathic concern, altruistic motives, and are less willing to accept offers of help from an outgroup than an ingroup member. However, this effect will appear mostly when people are highly prejudiced, when the intergroup interaction takes place in the ingroup context, or when they are exposed to an exclusive or intolerant ingroup norm or to a suspicious intergroup apology (i.e., an institutional apology). Likewise, I suggest that people in need undermine an outgroup member's assistance when they harbor a previous understanding that outgroup members have dehumanized them as a group. In addition, this dissertation explores the underlying mechanisms concerning these investigated effects. Drawing from previous literature and empirical findings in the domains of intergroup help and contact, I suggest that attributions of empathic and/or altruistic motives, perceived helper's capacity to assist, normative and personal perceptions about intergroup interactions, perceived outgroup humanity have the means to explain why, for example, people are less likely to accept outgroup help. These predictions have been tested through 17 experiments fully explained in the dissertation and 4 others briefly mentioned in its notes. Overall, the main findings are discussed in light of intergroup expectations, social identity, prosocial intergroup behaviors, and intergroup contact.