This study extends research on within-nation regional differences as well as the relationship between interpersonal trust and within-nation regional e-commerce by empirically investigating 44 regions of three European Union nations: Italy, Spain and Portugal. Within-nation regional trust data from the World Values Survey is used in conjunction with within-nation regional e-commerce data from the Eurostat Database. Results show that even after controlling for GDP, region size and population density, interpersonal trust is still positively and significantly related to within-nation differences in e-commerce adoption.