Soft drinks such as Pepsi and Coca-Cola are already barred. Parents and teachers are now being asked about extending the ban.
The English Secondary Students' Association, a representative body for school pupils, has criticised the proposed restriction on choices. "We would always advocate greater education about food rather than bans or compulsory restrictions on diet," said Jack Lewars, 18, the national student support officer. "I think students are capable of deciding for themselves whether they should drink tea or coffee."
The School Food Trust said the draft code of practice allows tea and coffee, even though they have minimal nutritional value. It describes this as an "obvious inconsistency".
Dr Michael Nelson, nutrition director at the trust, said children needed to be encouraged to choose water, or more nutritious options such as fruit juice or milk.
"If you want children to eat more healthily, then the range of choice in schools needs to be restricted to healthier options only," he said.
There was no suggestion that tea or coffee drunk in moderation had any particular adverse health effects, he said, but neither did they have much nutritional value.
Dr Nelson suggested that there might also be health and safety concerns about serving hot drinks in the school dining room.
James Looker, a teacher at Forestdale School in Croydon, Surrey, said he had been drinking tea since he was 10 years old. "I drink it all the time," he said. "It's nice and warm, and it gives me a caffeine-boost for the afternoon.
"Surely policymakers have something more important to worry about? If you ban things, that just makes them more attractive to kids, so they'll try harder to get them."