The pupil premium for school pupils from poor backgrounds will rise from £600 to £900, David Laws announced at Brighton.
The Yeovil MP was making his first speech as a government Minister at a Liberal Democrat conference.
The Schools Minister responded to a report by the education watchdog Ofsted last week that the cash was not working the way it was intended – to help disadvantaged youngsters catch up.
Ofsted chief inspector Sir Michael Wilshaw said there was a real concern the money was just being used to plug the gap in school budgets.
Mr Laws said the pupil premium, which is for those eligible for free school meals and children in care, now covered more than a quarter ofall pupils.
It had risen from £488 per child in the first year to £600 last year, and would be £900 next year.
He urged parents, teachers and governors to monitor the way schools used the money to ensure it was delivering results.
“I will hold schools to account – they must use the pupil premium money to help disadvantaged pupils to catch up, and you can help make this happen."
Mr Laws also announced £100 million of extra funding to pay for summer schools for disadvantaged children, to help them when they switch from primary to secondary schools.