Research on helping and altruism has been revitalized by the shift in focus from individual and interpersonal processed to group processed in the last decade. In particular, the social identity approach (Tajfel & Turner, 1979; Turner, 1985; Turner, Hogg, Oakes, Reicher, & Wetherell, 1987), which ahs been increasingly applied to helping situations, has provided a valuable group perspective on helping behaviour. The significance of social groups and shared identity for altruism has also been suggested (e.g., Monroe, 1996; Sober & Wilson, 1998). Although helping and altruism are typically undifferentiated, central to altruism is the issue of motivation, which as additional theoretical and applied implications. The eight studies reported in this thesis aimed to build upon current social identity research on helping behaviour and to extend the social identity approach to altruism. In line with the social identity perspective, factors associated with group membership were expected to have important implication for individual helping decisions, especially among high identifying group members. Studies 1 to 3 tested the combined effects of target group membership and group identification on individual helping intentions. In all three studies, participant completed an ingroup identification scale and reported their intentions to help the target, who was either an ingroup or an outgroup member. Consistent with expectations, high identifiers were willing to offer more help to a more ingroup-like target in study 1 (N = 141). However, in Study 2 (N = 93). High identifiers offered more help to an outgroup than to an ingroup target. In an attempt to clarify these conflicting finding, Study 3 (N = 138) examined group members’ helping responses in a group-relevant and a group-irrelevant helping situation. Results indicated that high identifiers were more willing to help an outgroup target when the helping situation was group-irrelevant rather than group-relevant. The helping intentions of low identifiers were largely unaffected by the group membership of the target or the group-relevance of the helping dimension. In a further analysis of the impact of target group membership on helping behaviour, Study 4 considered the moderating effects of perceived need on intergroup helping decisions. Using a realistic helping paradigm, participants (N = 94) heard a voice recording of a request for help from either an ingroup or an outgroup target, who expressed either a high or a low need for help. Where as people were more likely to help the ingroup than the outgroup target when there was a high need for help, the group membership of the target did not affect helping decisions when the need for help was low. While Studies 1 to 4 elaborated on the role of social identity factors in intergroup helping contexts, Studies 5 and 6 Focused on helping with intragroup contexts by considering how the intragroup position of the target can also influence people’s helping intentions. In Study 5 (N = 166), social identity salience was manipulated, whereas ingroup identification was measured in Study 6 (N = 118). Participants in both studies were then presented with a profile of either a prototypical or a non-prototypical target and were asked to indicate their helping intentions. As predicted, people who perceived their ingroup identity to be more salient (Study 5) or identified more highly with the ingroup (Study 6) were willing to offer more help to the prototypical than to the non-prototypical target. In addition, concern for the target was found to be a mediator in predicting individual helping intentions. The final two studies investigated social identity processed in field settings. Study 7 (N =618) assessed both helping intentions and behaviour in the context of a charity door-knock appeal. Respondents in both studies completed a survey, which included measures of group identification, concern, and helping intentions. Greater identification with the group was associated with increased willingness to contribute to the community (Study 7) and intentions to donate more money to the door-knock appeal (Study 8). Further more, the relationship between group identification and individual helping intentions was mediated by concern. Together, these eight studies highlighted the complexities of social identity influences on helping behavior as well as the contributions that the social identity approach can make to the study of helping and altruism.