The current dissertation examined the impact of (mis-)fit between individuals’ achievement needs (individual goals) and the group’s potential to fulfil these needs (group goals) on strategies to regulate need fulfilment. It was argued that group members can adopt several strategies to cope with experiences of goal-divergence. These strategies were goal negotiation, goal adjustment, and exiting the group. Four studies were conducted that manipulated vs. measured goal-divergence, that involved tasks that emphasized individual accomplishments vs. responsibility toward the group outcome, and that used experimental vs. natural groups. The psychological impact of goal-divergence was immense. Goal-divergence affected identification with the group, affective rejection of the group, intentions to exit the group, individual goals and group goals, beliefs about group efficacy and self efficacy and commitment to individual goals. In addition, responses to goal-divergence varied as a function of how important group membership was regarded. For example, in the context of a soccer team, low, as opposed to high identifiers reported more exit-intentions when goals were divergent. Finally, especially those individuals who regarded group membership as important found very creative ways to prolong the group’s potential to fulfil their current needs, for instance by adjusting the individual goal (assimilation) or by adjusting the group goal (accommodation). One can conclude that goal-divergence impacts on group functioning, on individual functioning within groups, and on the relation between individuals and groups. The current dissertation underlines that the relationship between individuals and groups must be approached bidirectionally (Jetten & Postmes, 2006; Packer, 2008) and demonstrates the dynamic and ongoing usage of need regulation strategies that individuals use to make the relationship between themselves and their groups most rewarding for both sides.