Google has denied it broke its promises on using children's personal data.
Civil liberties group the Electronic Frontier Foundation (EFF) accused Google of collecting and storing data from children using its products at school.
It asked the US Federal Trade Commission (FTC) to investigate.
But Google said it used the data only to improve its products and services and not to target adverts - in line with its commitments.
In a complaint filed with the authorities earlier this week, the EFF said Chromebooks supplied to schools as part of its Google Apps for Education (GAFE) project came with a feature designed to synchronise the Chrome browser across devices, which transferred students' data without permission.