The school competed against 540 schools from New Zealand and Australia in the online competition, which tested pupils' foreign language skills.
Pupils were asked to translate single words from one of seven languages into English, receiving one point for every correct translation.
The languages included Te reo Maori, Italian, French, Spanish, German, Japanese and Indonesian.
Otago Girls High School had 427 pupils in the competition, and they scored 295,482 points between them.
Their strongest contributor, year 11 pupil Alana Mills, spent almost four hours a day over the three-week competition to get her high score of 10,027 points.
"I started out with Spanish and then as the competition ended I tried out French.
"I want to continue with Spanish and get a degree in languages from Otago University, so I can become an interpreter," Alana said.
Dunedin's Mayor, Peter Chin, who presented the top award, encouraged the girls to continue using language to break down cultural barriers.
New Zealand Association of Language Teachers president Adele Scott said the competition was a great way to make one of the more monotonous parts of learning languages fun.
She said in order to have a good understanding of another language you needed to know about 2000 words.
Ms Scott said students who learnt every word taught in NCEA level 1 learnt about 700-1000 words, depending on the language.
The software used for the competition was developed and run by a Dunedin student, Craig Smith (20), and his brother Shane Smith (23).
The brothers believe the greatest success story in this year's competition was Gore High School, which finished third.
The decile three school proved that quantity does not always mean quality, with its team of 123 pupils scoring 15,2620 points, an average of 1240 questions answered per pupil.
Head of languages at Gore High School Chris Sheyn credits the school's high placings to a great spirit.
"It was a real team effort, which you can get in smaller schools," he said.
