We study whether a better knowledge of the functioning of pay-as-you-go pension systems and recent demographic trends affects natives’ attitudes towards immigration. In two online experiments conducted in Italy and Spain, we randomly treated participants with a video explaining how, in pay-as-you-go systems, the payment of current pensions depends on the contributions paid by current workers. The video also informs participants about population aging trends in their countries. The treatment increases knowledge of pay-as-you-go systems and future demographic trends for all participants. However, it improves attitudes towards migrants only for treated participants who do not support populist and anti-immigrant parties.