Holly Helbert, a pupil of Douglas Academy, won the competition, organised annually by the Scottish Review in conjunction with the Young Programme charity, with a heartfelt essay on a family bond and grief.
One of the judges, Times columnist Magnus Linklater, described Holly’s essay as: "Beautifully told, poignant, simple, about coming to terms with childhood, growing up and the loss of a close relative.
"The construction of the piece held it together”.
Another of the judges, broadcaster and writer Sally Magnusson, said: "A stylishly written tribute to a grandmother.
"Moving, without ever straying into sentimentality”.
While writer James Robertson, commented: “Full of fine descriptions and very mature observations.”
Another Douglas Academy pupil Sarah Reid Bendoris was highly commended in the competition for her “well-written review of French film, La Heine”.
Holly received a cheque for £600 for her winning entry which has been published in a special edition of the Scottish Review, while Sarah received receive a certificate of recognition and book token.
The contest was open to pupils in Scottish schools who were between the ages of 15 and 18 years old.
Pupils were asked to imagine they were writing a non-fiction feature or column for a magazine or newspaper, between 900 and 1,200 words in length.
Judge Keith Aitken, a journalist and broadcaster, added: “Picking three from the shortlist has never been harder in the years I've been involved.
"All our shortlisted writers can be proud of their achievement.
"They produced writing worth reading, and all of them have the potential to make a lifelong success of writing.
" I hope they enjoyed the experience sufficiently to do so”.
A spokesperson for the Scottish Review said: “Our congratulations to all 21 long-listed pupils for their outstanding work and to the many other promising young writers who entered the competition.”
You can view Holly’s prizewinning essay at www.scottishreview.net