Matti Juhani Saari (May 20, 1986 – September 23, 2008) was a Finnish school shooter who killed 10 people at a vocational school in Kauhajoki where he was training to become a chef. He expressed his apparent motive with the sentence: "I hate the human race. The solution is a Walther P22".

Friends who knew Saari described him as a happy social guy, who abruptly developed an obsession with guns. It is revealed that Saari was bullied chronically, for example, threats were made to break his scooter and he was spat on frequently.

The day before the shootings, Matti Saari was investigated by police after he posted videos of himself shooting at a shooting range. The police said that they couldn't detain Saari as he was in legal possession of a gun license. The night before Saari became a killer, he remained calm and looked normal, talking to his friend regarding the exam for the next day.

On the day of the attacks, Saari barged into the exam hall where he was supposed to take a business studies paper. It was 90 minutes into the exam, when he opened fire and shot everyone in sight. He fired more than 200 shots, including shots to the air and the highest amount of shots inflicted into a single victim was more than 20. He then burned the bodies to beyond recognition. After wandering around the school for quite some time and calling a pal to say goodbye, Saari shot himself in the head and died.

He also left a note for his buddy telling him to look at Virginia tech killer Cho's manifesto, which Saari described as awesome.

Matti Saari was also a friend of Pekka-Eric Auvinen, the teen who shot up Jokelan Koulukeskus less than a year before. They even bought their gun from the same shop.