Social trust is at the center of democratic societies but it varies considerably between individuals and societies, which deeply affects a range of prosocial behaviours. Socioeconomic status has been identified as an important predictor of such variability. Although this association has mostly been reported for measures of socioeconomic status taken in adulthood, recent studies have found unique effects of harsh conditions experienced during childhood on social trust assessed decades later. Here, we report a series of three studies that provide further support for the long-lasting association between early childhood conditions and social trust. The first study revealed that higher childhood socioeconomic status was associated with greater social trust in a diverse sample of French participants (N=915), even after adjusting for current socioeconomic status. The second study replicated this result using data from the European Values Study, an independent large-scale survey of 46 European countries (N=66,281). Finally, the last study found a similar association between socioeconomic status and willingness to invest in a trust game (N=60 in original study, N=75 in replication study).