Extreme Dialogue was launched at Quintin Kynaston, the school once attended by Mohammed Emwazi, who became known as "Jihadi John".
The scheme uses the stories of people who have been radicalised in the past.
Organisers said it was "vital" to give pupils "skills to challenge extremism".
"Only by discussing extremism openly can we ensure young people understand its corrosive impact", Jonathan Birdwell of the Institute for Strategic Dialogue said.
The programme started in Canada in 2015 and is aimed at pupils aged between 14 and 18.
It provides films and exercises involving people who have previously been affected by extremism.
One man involved is Billy McCurrie, who joined the Ulster Volunteer Force (UVF) when he was 16 after his father was killed by the IRA.
"If through this project I can reach one young person... and it causes them to stop, think, and not go down that road, it'll all be worth it," he said.
Adam Deen, a former member of the now banned Islamist group Al-Muhajiroun, is also featured.
The Extreme Dialogue films and resources will be available to UK schools during the 2016-17 academic year.
A ruling a year ago made it a statutory duty for schools to prevent pupils being drawn into terrorism.
A spokesperson for Quintin Kynaston said the programme was "a great tool to open up discussions" about extremism.
Islamist militant Emwazi, who appeared in several hostage videos for so-called Islamic State, attended the school over a decade ago.
The headteacher at the time has said he was never suspected of being radicalised at the school.
A UK-wide programme aimed at teaching young people to stand up against extremism has been launched in a north-west London school.