The film details the lives of 17 teenage schoolmates in 1950s Denmark.

Shooting on location at the high school which he had attended, Malmros took two years to film the action, so the cast members reflected the real-life physical and emotional development of their characters.

[5] When Nils Malmros called Gitte Iben Andersen to say that she had been chosen to play Lene, she objected that there was a group nudity scene.

She initially refused to play the scene for that reason but eventually agreed when Malmos remarked that all other girls had accepted the scene, without realising that he had used the same trick with them.

[6] Film Critic Roger Ebert of the Chicago Sun-Times wrote "The Tree of Knowledge is the truest and most moving film I have ever seen about the experience of puberty... a creative act of memory about exactly what it was like to be 13 in 1953.