The Prince of Wales has warned of the importance of "teaching the whole person" rather than just providing an academic education.
He suggested that the "element of character" has been "left out of the equation" for far too long.
In a speech to the Prince's Teaching Institute (PTI) on Wednesday, Charles praised teachers for inspiring today's youngsters in many different ways.
The PTI, established to encourage teachers to rediscover their passion for their subject, is holding its second head teachers' seminar at Madingley Hall in Cambridge.
Addressing delegates, the Prince said that good leadership can make "the ultimate difference" to a school.
"One also understands the essential importance of teaching for the whole person, teaching, educating, character as well as just the academic side," he said.
"But it seems to me that one of the things that has been left out of the equation for so long is the element of character."
The Prince said that he knew from his 36 years of the Prince's Trust that "one of the key issues we have to face is how to raise self esteem, self worth and self confidence."
So many of the young people they deal with have low self esteem, low motivation and low aspirations, he said, adding "that has to be raised".
The Prince's Trust run courses and programmes that have helped many young people turn their loves around.
Charles said: "The point is, I believe we have to raise the level of esteem for many people before they can access the real value of education, whether academic or vocational, or both."