Lutterworth College has been given the go-ahead by the Department for Education to accept 11-year-olds from August 2015.
The school says the move is the biggest change in its 134-year history.
Executive principal Andrew Cooper was delighted with the Government approval for the changes.
He said: “We are very excited by this news.
“Parents have been ringing me up for weeks asking if we had got approval to accept 11- year-olds. Now we can put all our exciting plans into action.
“We know from talking to parents that many families will welcome the opportunity to send their child to one school from the age of 11 all the way through to 18.”
The school held an open vening for parents on Wednesday, June 18, at which parents and children could find out more about what the school has to offer.
Mr Cooper added: “It was a fantastic opportunity to showcase everything that we have to offer.
“In particular, parents were able to meet our specialist subject teachers, find out about the 30 or more different courses that are on offer and learn about the new base for Year 7 children, called The Laurels.”
In addition, Mr Cooper was able to announce to visitors that the school’s 2013 results has placed Lutterworth College within the top 15 per cent of schools in the country based on the Government’s new “Progress 8” measure.
He said: “This news justifies our belief that our tried and tested curriculum model is well suited to the way education is progressing and it tells us that our expert staff deliver high-quality results in both academic subjects and vocational qualifications.
“This will give parents absolute confidence that if they send their child to Lutterworth College, they will achieve higher GCSE grades than if they went to similar schools with a similar intake, whatever their ability.”
A number of other schools in the district are also bidding to change their age range.
Parents of pupils at Welland Park Academy in Harborough are being consulted on plans to change from being an 11 to 14 school to an 11 to 18 establishment.
That consultation runs until June 23.
Parents of children at Robert Smyth Academy have also been consulted on similar plans.
And Kibworth High School is also in the process of making changes to becoming an 11 to 16 school.