Ken Livingstone has promised to bring back the EMA to encourage disadvantaged students to stay on at school if he is reinstated as London's mayor in May.
The education maintenance allowance was abolished in January 2011, despite widespread opposition against the move.
The scheme, which would only be available to London teenagers, would provide up to £30 a week for students to stay on at school or college.
Livingstone said he wanted to "ease the squeeze" imposed by the government on to students.
"I have been deeply struck by the plight of thousands of students I have met at colleges right across the capital, who have had the lifeline that EMA offered snatched away from them by the Conservative party, whilst the part-time Tory mayor stood by."
The National Union of Students (NUS) has welcomed the announcement, saying it set a "powerful example to national policy-makers".
Toni Pearce, NUS vice-president of further education, said: "Reintroducing EMA in London would be a huge step towards making sure that all young people in further education receive proper financial support to pay for the bare essentials associated with studying and would set a powerful example to national policy-makers."
"Instead of washing their hands of the government's decision to pull the plug on EMA or protesting their powerlessness, the other mayoral candidates should follow Ken's lead and commit to reintroducing EMA.”
James Mills from the Save EMA campaign added: "This is great news for tens of thousands of the poorest teenagers in London; it means that they can once again take education as far as their ability lets them and not their ability to pay.
"Boris has defended a minority of the wealthiest bankers on a regular basis, and only once has spoken out on EMA, and then only briefly. Its time Boris shows he is the Mayor of London not the Mayor of bankers.
"This will not only set down a marker for other mayoral contests across the country, but has shown it is not about money, but about priorities when it comes to down whether teenagers should have EMA payments."