The bank says parents are compromising their children's future financial security with so much online sharing.
Barclays forecasts by 2030 it could cost almost £670m in online fraud.
The bank's security specialists say social media means identity fraud has "never been easier".
Barclays is warning that parents might be "lulled into a false sense of security" and fail to realise they are making their children "fraud targets" in the future, by publishing so much personal information which will remain online.
Identity fraud