The education department proposed axing it to save money. But the issue proved so controversial that politicians deferred a decision at this week's budget meeting of the island's parliament.
Free milk will stay until the end of February. Meanwhile, there will be a debate in the new year, and the health and social security departments may help to foot the bill.
It is the third time in six years that the education department, which has a Pounds 55 million budget, has tried to shed the milk bill.
Senator John Rothwell, a former president of agriculture and fisheries, condemned it for "penny pinching".
Jersey's education director, Brian Grady, under pressure to save Pounds 1m, claimed that he had to abolish free milk or abandon plans to provide more ancillary teachers.
The annual cost of providing free milk to an estimated 6,500 pupils is Pounds 175,000. "From the educational point of view, expenditure on milk is not a high priority," said Mr Grady. "But we think that having extra ancillary help in every class where there are under-fives would be of immense benefit."
Controversy has intensified after the British Medical Journal reported that the centre for human nutrition at Sheffield University had found that bone density and content among schoolgirls who drank half a pint of milk daily for 18 months was much improved over their peers who did not have milk.
Mr Grady claims that all heads in Jersey say that the money would be better spent elsewhere. But many islanders disagree.
"We enjoy some of the best standards of living in the world, yet there are a lot of deprived homes in Jersey," said Senator Rothwell. "By keeping school milk, you allow good habits to develop - health education starts at school. "