An investigation has revealed that more than £10,000 in overpayments dating back to 2004 was being held by Outwood Grange Academy last month.
The cash was lying in 13 separate accounts set up to process payments for previous trips to France, Spain, Germany, Geneva and Bruges.
The Express found that on September 3, £10,034.89 was still outstanding at the Potovens Lane school.
Outwood Grange said it had already discovered the amounts outstanding in a reorganisation of the school’s finance system and parents were being repaid.
The school said in a statement said: “As we were routinely moving account balances from the old system to the new system, monies were identified that related to trips run by the academy in previous years.
“This process began in April 2012. As these balances were identified the academy began refunding parents and carers.”
The school said a total surplus of £12,241.82 was identified and £10,352.00 of this had been refunded to date.
Surpluses from school trips were divided up and refunded with a letter to parents.
Outwood Grange expected to refund all monies, but if parents could not be traced the cash would be used to help families who could not afford to finance school trips themselves.
The school did not benefit financially from the balances held, the statement said.
One of 13 trip accounts was holding £872.27 in overpayments for school trips between 2004 and 2008.
There was £2,983.96 outstanding from trips abroad in 2009, £2,310.30 from 2010, £2,941.07 from 2011 and £927.29 for trips earlier this year.
Outwood Grange said it made 44 refunds to parents in 2011-12 - but so far this financial year has made a further 283 refunds.
A Department for Education spokesperson said: “We have received a complaint about Outwood Grange Academy. We have contacted the academy Trust which was already aware of it and are looking into the matter.”