The teaching of information and computer technology (ICT) is inadequate in a fifth of secondary schools, according to the education watchdog.
Pupils' achievement in the subject is hampered by a lack of challenges and poor coverage of key aspects of the curriculum, the Ofsted report said.
Half of students reached the age of 16 without adequate foundation for further study or training in ICT in 30 of the 74 secondary schools Ofsted visited.
Chief Inspector Miriam Rosen said: "In a world that is becoming increasingly reliant on technology, young people need to be given the opportunity to learn ICT skills in an interesting, challenging and relevant way.
"Schools should provide a range of ICT courses that are suitably matched to students' needs, support them with their learning and prepare them for higher education and for skilled work in a technological age."
In August, Google chairman Eric Schmidt said he was unimpressed by the level of ICT teaching in Britain.
"Your IT curriculum focuses on teaching how to use software but gives no insight into how it's made," he said at the annual MacTaggart lecture in Edinburgh. "That's just throwing away your great computing heritage."
Ofsted said it found "weaknesses" in the teaching of programming and databases in both primary and secondary schools.
Last month, a report published by the Department for Culture, Media and Sport found ICT teaching to be "insufficiently rigorous and in need of reform".
This year, 31,800 students took GCSE ICT, compared with 81,100 in 2007 - a 61% reduction, but more students are taking vocational courses, with 212,900 completing OCR Nationals this year, compared with 58,900 in 2008.