Social sciences have thoroughly investigated how values of solidarity vary across age cohorts. Whether and how religiosity mediates attitudes towards solidarity has received much less attention. This study addresses this issue. Building on the literature suggesting that Gen Xers and Millennials express a stronger demand for the inclusive facets of religiosity, it argues that generational gaps in altruism can be mitigated by the more positive influence religiosity exerts on younger cohorts. Results show that age cohorts are polarised on social altruism - i.e., concern towards the worse-off -, but that generational differences strongly decrease with both increasing religious belief and behaviour. Religiosity thus emerges as an unexpected driver for change, capable of bridging generational gaps in social altruism.