They were falling behind girls in modern foreign languages and geography. Foreign languages, in particular, were in danger of becoming a subject just for middle-class girls, David Bell, chief schools inspector, said.
Boys' worst performance was in French GCSE, in which only 46 per cent obtained a top grade pass, his annual report said.
Since the Government made study of languages voluntary after the age of 14, only half the country's pupils have continued to study it, with take-up particularly low in disadvantaged areas.
Mr Bell said: "Teenage boys are not necessarily prepared to speak much English, let alone French and German."
By contrast, boys were doing better than girls in maths - both in primary school tests and at GCSE. "Girls are often less assertive in the classroom setting and less willing to venture an idea than boys are," Mr Bell said.
However, in some schools which had pioneered single sex classes in science - despite being a mixed school, performance in the subject had improved.
"That's not a panacea and it would be wrong for anyone from Whitehall to lay down the law to an individual school, but it has benefited some schools," Mr Bell said.Reuse content