Academics have claimed that many young people are disadvantaged because families in higher income brackets are five times more likely to be connected to the internet than those with lower incomes.
But Professor Greenfield, director of the Royal Institute and an expert in neuroscience, told The TES that, overall, the internet was having a "democratising influence" on education.
"For centuries we have had families where parents have read to their children and other homes with no books at all," she said. "At least now a child whose parents do not have books may get access to a computer."
Professor Greenfield wants to make it easier for lower-income families to buy computers as it would improve their education.
The neuroscientist was this month promoting The BT Learning Centre, a subscription website which connects children to a range of educational material.
Professor Greenfield had previously claimed that young children risked developing "standardised brain connections" from using computers because of the information they provide.
However, she said she did not think there was any danger the BT website would damage children's brains as it would encourage them to make choices about the information they read.
A survey published by the BT Learning Centre this week suggested that children with internet access were 43 per cent more likely than others to give their homework extra attention.