New figures, published in a report that went before councillors this week, show that children looked after by the city council do "significantly less well" than the rest of the school population.
Only 0.7 per cent of looked-after children living at home - and 2.1 per cent of those away from home - get five or more Standard grades at Credit level or Intermediate 2 in S4; that compares to 22 per cent of Glasgow S4s overall.
Some 14.8 per cent of looked-after S5 pupils living away from home get one or more Highers (compared to 28 per cent of all Glasgow S5s) but only 3.7 per cent of the same group gets three or more (compared to 14 per cent overall).
There are no statistics for Higher passes of looked-after children in S6 - because, the report starkly observes, "too few children and young people remained at school until S6 and those who did remain passed few or any SCQF qualifications at this level".
Gordon Matheson, the city council's executive member for education and social renewal, wrote the report with Elaine McDougall, executive member for social care.
"We are producing these figures in the interests of transparency - we are not proud of them, we don't think they are good enough, and that's why we are throwing light on the situation," he said.
"This is the group which is performing worst of all. It is our clear responsibility to face up to and improve that."
He stressed that Glasgow had the highest number of looked-after youngsters of any Scottish local authority.
In March of this year, 2,915 children were deemed to be looked after by the city council, of whom 1,722 lived at home while the others were in various forms of accommodation, including foster care, residential schools and secure units.
Mr Matheson wants the city's new "champions board" for children and young people to make the educational performance of looked-after children a priority.
The board, which is to meet six times a year, will be comprised largely of senior figures in education and social work - both staff and councillors.
Mr Matheson said work had already begun on improving pass rates for looked-after children, but it was too early to give details.
The board will also look into coming up with specific targets for the attainment of looked-after children.
Meanwhile, Mr Matheson said that Glasgow's approach to "corporate parenting" would match that of Inverclyde Council, where senior figures in the authority are to be individually responsible for a specific looked-after child.
"As elected members and as senior officials, we are legally and morally responsible for the care of these children, as if they were our own," he said.
"I do envisage that senior officials and councillors would take a particular responsibility for specific children and young people within our care."
He remains open-minded about how this will work in practice. Corporate parent and child are not expected to meet in Inverclyde Council - young people will not even be told their corporate parent's identity. But Mr Matheson did not rule out the possibility that they would meet on occasions in Glasgow.
A separate report on the city council's corporate parenting responsibility made clear how closely the authority should imitate real parents - right down to remembering birthdays and providing "occasional financial support".
The Glasgow City Council reports follow the Scottish Government's announcement in October of pound;2.5 million for local authorities to enhance their roles as corporate parents.