Social identity is a key social psychological variable to understand intergroup behaviours. Over and above the different dimensions of social identity (e.g., quality or degree of identification), recent research has looked at different forms of social identity, such as the clarity of one's collective identity, the self-determined motivations underlying one's identification, and the contingencies attached to social identification. These forms of social identification reveal how and why group members are attached to their social group. The current research aims to directly test how these three forms of social identification regroup together and predict different individual and intergroup outcomes. Findings from three studies conducted in Québec (Ns = 119, 91) and Australia (N = 136) confirmed that the more comparative and competitive forms of social identification (i.e., non-self-determination to identify, collective self-esteem contingency) tend to predict nationalism and ingroup bias. In contrast, the forms of social identity that capture the inherent satisfaction of being part of the group and the cognitive clarity of this group membership (i.e., self-determined motivation to identity, clarity of collective identity) predict outcomes pertaining to patriotism, personal self-esteem, and positive emotions. Results are interpreted in light of social identity theory and social psychological models of the self.