The handgun attack - the first of its kind in the country - has caused particular shock because the Netherlands has strict firearms laws.
A day after a 13-year-old opened fire in a school in Tulsa, Oklahoma, gunfire broke out about 2pm in the southern town of Veghel as the teenager sprayed shots in a hallway and computer room of De Leijgraaf school.
Early indications were that the attack was probably not a copycat incident after Oklahoma. Some reports said the pupil may have been depressed because of a failed romance, others that he was upset about a relationship involving his sister. The suspect later turned himself in to police in the town.
Although there was confusion over injuries, at least one victim was seriously hurt and said to be in a critical condition. There were reports that the teacher, a 46-year-old woman, was seriously injured.