Eighteen-year-old Shima Jack, of Dunedin, summed up how the honour felt with two words: "very weird".
The Logan Park High School pupil won the Sargeson Prize secondary school division after the judge selected her work out of 165 entries.
Although she won last year, she had no expectations of winning again, she said.
Writing was a very subjective art and the judges would have different tastes.
It made this year’s award even more surprising than her first.
Her winning story, called Fourth Wall, addressed the theme of gender roles in children and how things changed as they grew into teenagers.
The plot followed a pair of childhood best friends who went to see a play together, but their true colours were shown when a fight broke out.
It was based on the experiences of her and her friends, she said.
The prize is a week-long summer writing residency at the University of Waikato, as well as $500.
That residency had been great last year and had helped her develop her skills, she said.
This year she hoped to focus on planning her work better and communicating her ideas.
She had done a University of Otago English paper this year and had greatly enjoyed it, so knew she wanted to go to higher education, but had no confirmed plans yet.