The device went off just before 8 a.m. in the Adriatic port town of Brindisi just as students milled outside, chatting and getting ready for class at the vocational institute named after the slain anti-Mafia prosecutor Giovanni Falcone and his wife.
Falcone and his wife were killed by a Mafia blast in Sicily exactly 20 years ago this weekend, but it was unclear if there was an organized crime link to Saturday's explosion.
There were no immediate claims of responsibility.
Just three days ago, government officials announced security was being stepped up throughout the country, following a shooting which wounded a nuclear energy official and several threats or explosions of devices at offices of a tax collection agency.
In Brindisi, local civil protection agency official Fabiano Amati said a female student died of her wounds after being taken to a hospital and seven other students were hospitalized.
Sky TG24TV said the victim was a 16-year-old girl.
Officials initially said the device was in a trash bin outside the Morvillo-Falcone school, 루비맞고 but later the Italian news agency ANSA, reporting from Brindisi, said the device had been placed on a low wall ringing the school.
Public high schools in Italy hold classes on Saturday mornings.
The bombing also follows a number of attacks against Italian officials and government buildings by a group of anarchists, which prompted authorities to assign bodyguards for 550 individuals and deploy 16,000 law enforcement officers nationwide.
Austerity measures, spending cuts and new and higher taxes, all part of Premier Mario Monti's plan to save Italy from succumbing to the debt crisis roiling Greece, have angered many citizens, and social tensions have ratcheted up.