Only one in a hundred children in care is going on to university this autumn, compared to 43% of the under 30s, a survey has found.
Children in care are much less likely to get GCSES or equivalents
A study for the children's charity NCH also says the educational gap between children in care and others has grown by two percentage points since 2000.
In England in 2004, 6% of children left care with good GCSEs or equivalents compared to 53% of pupils overall.
The charity says society is letting children in care down.
The study says in the best performing local authority, 83% of children leaving care achieve at least one GCSE or GNVQ; in the worst it is just 16%.
NCH chief executive, Clare Tickell said the gap in achievement between children in care and others was a "systems failure".
"Children in care are the responsibility of the state and how well we serve them is a measure of how our society treats children more generally," she said.
"At the moment we are letting them down and consigning many to social exclusion when they grow up. If we do not tackle this issue today it will cost society tomorrow."
The charity supports children in care and encourages them with their education. It says 43 care leavers supported by NCH projects are at university this year.
Among them is Alex Sykes, 24, who is about to start his third year at Huddersfield University. He was in care from the day he was born.
"I'm the only one of my friends from care at 'uni' and most of them aren't in education. In lots of ways it annoys me that I'm the only one because it's not like I'm any better or smarter than they are.
"Coming from a care background doesn't make you stupid, it just means you've been through a lot and need extra support.
"I had loads of residential and foster placements and only one of them had a positive impact on my education. If it hadn't been for that I wouldn't be doing so well today.
"Other kids from care aren't empowered to believe in themselves and don't get the encouragement that meets their individual needs."
NCH is urging the government to make the underachievement of children in care a high priority and to close the attainment gap by 2020.
Statistically, children in care are more likely to have learning and behavioural difficulties and mental health problems than the rest of the population.
More than two in three live in foster care, while only about one in 10 live in a residential care home.
NCH says the attitudes of foster carers to education is therefore important.
Children's education is often disrupted by their being moved between placements, they often end up in the worst-performing schools and often miss school. They also suffer from the low expectations some teachers have of them, the charity said.
A spokesperson for the DfES said: "The achievement of looked after children is unacceptably low compared to their peers and we are acting to make a step change to close the gap.
"Many of the report's recommendations mirror those made by the Social Exclusion Unit which the DfES has been implementing.
"We already recommend that looked after children should have priority in schools over-subscription criteria and the Education Act gives that advice statutory force.
"Schools are responsible for promoting the educational achievement of all their pupils. It is hard to see what a specific duty to promote the educational achievement of one particular group of children would achieve."