The scheme is run by ACCAC, the Welsh qualifications, curriculum and assessment authority, which will become part of the government's new education, lifelong learning and skills department from April 1.
An ACCAC spokesperson confirmed that this year's winners of the school improvement index scheme, supported by the HSBC bank, would be the last.
The news makes Barry comprehensive's third successive award for most improved school in Wales - announced this week - a special achievement.
David Swallow, headteacher of the single-sex boys school, which has introduced vocational courses in ICT, performing arts, and hospitality and catering, said: "We are absolutely delighted to win the ACCAC award for the third year in a row. It is a testament to the dedication of the staff and highlights the increased opportunities for these students post-16."
A Swansea Valley secondary school, renowned for nurturing emerging rugby talent, has received recognition for its steady rise up the school improvement table. Cwmtawe comprehensive, in Pontardawe, is among four schools to receive regional improvement awards from ACCAC.
The school, which numbers former Welsh rugby internationals Robert Jones, Arwel Thomas and Bleddyn Bowen among its past pupils, attributes its high performance in key stage 4 results to a tracking system used for all year groups, as well as an extensive out-of-hours programme.
Head Alan Tudor Jones said: "Although the school is delighted with its GCSE pass rate for five or more A*-C grades (72 per cent in 2005), one of our proudest achievements over the past six years is that fewer than 3 per cent of pupils have left with less than five or more A*-G grades."
Under the school's tracking system, pupils are set targets for attainment in Year 7. They are then monitored throughout their five years at school so that they maintain the highest standards at KS3 and KS4.
"We are lucky to have an extremely committed staff who give their time freely to support the children," said Mr Jones.
Other regional awards went to Wrexham's Maelor school, Welshpool high school in Powys, and Cwmcarn high school, in Caerphilly.