Adolescents in French-speaking cantons showed the best reading skills, while school-goers in German-speaking regions scored highest in science subjects and mathematics.
The results come from a regional breakdown of figures from the latest Programme for International Student Assessment. Better known as the PISA report, it evaluates educational competence in the OECD countries every three years.
A year after Switzerland released the national results of the 2009 report, 13 of the 26 cantons have now presented their own figures. These show significant discrepancies between the three linguistic regions.
According to the department of education in Ticino, the poor results in the Italian-speaking part of the country are partly attributable to the fact that pupils finish their mandatory education at a younger age (15.1 years old) than students in German and French-speaking cantons (15.9).
Pupils in French speaking cantons topped the reading test with an average of 506 points, followed by German speakers with 502 points, and Ticino with 485.
These roles were reversed for mathematics, with German-speaking students excelling with an average of 539 points, compared to 530 in French-speaking cantons and 518 in the Italian-speaking region.
The results were similar for natural sciences, where German-speaking cantons produced the best results with 523 points, followed by the French-speaking region (500) and Ticino (493).
Cantons Aargau, Fribourg and Schaffhausen obtained the highest average score across the three subject areas, while Geneva produced the lowest aggregate results, followed by Ticino.
Zurich, the most populous canton in the country, was the worst performer among the German-speaking cantons.
The head of the canton's education department, Regine Aeppli, said the comparatively poor results in Zurich were linked to the fact that 29 percent of students belong to socially disadvantaged families or are the children of immigrants, Tages Anzeiger reports.
In all, Switzerland scored above average in the PISA study. The country's 501 points put it above the OECD average of 493.