The positive relationship between religiosity and life satisfaction is well-established. This relationship is, however, likely to vary across cultural contexts and different religious affiliations. Furthermore, research is needed to uncover why religion is relevant for life satisfaction. Addressing these issues, we investigate what dimensions of being religious play a role in the life satisfaction of individuals with different religious affiliations, including the understudied Muslim category, in the highly secularized Dutch context. We examine ‘believing’, which captures how religion provides meaning and a coherent worldview, and ‘belonging’, which comprises both cultural benefits of being embedded in a congregation with a shared framework of meaning and structural benefits due to more social ties. Analyses of the NEtherlands Longitudinal Lifecourse Study (n = 5312) first indicate that Muslims display significantly lower life satisfaction than the non-religious, which appears to be due to their underprivileged social position rather than intra-religious factors of believing and belonging. Second, we find that Catholics experience significant life satisfaction benefits compared to those who are not religious, and that only belonging plays a role in this association. Next to the beneficial effect of the structural aspect of belonging, which revolves around social ties, a cultural aspect of religious belonging appears to be salient, suggesting that an important life satisfaction advantage of religious communities lies in their ability to foster a sense of solidarity and commitment through a shared framework of meaning. We make several recommendations for further research based on these findings.