Tabichi teaches science to high schoolers in the semi-arid village of Pwani where nearly a third of children are orphans or have only one parent.
Under Tabichi's mentorship, students from Pwani Village came first in the public schools category of Kenya's Science and Engineering Fair a year ago, with a device that enables blind and deaf people to measure objects. "I feel so happy to be among the best teachers in the world, being the best in the world", he told The Associated Press after his win.
He says: "To be a great teacher you have to be creative and embrace technology".
As a teacher working on the front line I have seen the promise of its young people - their curiosity, talent, their intelligence, their belief. Africa will produce scientists, engineers, entrepreneurs whose names will be one day famous in every corner of the world.
The Keriko Mixed Day Secondary School in Pwani Village, Nakuru County, emerged victor out of 10 finalists who were among 10,000 applicants for the award.
According to information on the award website, more than 90 per cent of his pupils are from poor families and nearly a third are orphans or have only one parent.
Peter Mokaya Tabichi with outgoing Education Cabinet Secretary Amina Mohamed
Tabichi (36) emerged the victor from a top list of 10 nominees from Brazil, Georgia, Netherlands, United Kingdom, India, United States, Argentina, Australia and Japan.
Emotion ran high at the final ceremony at The Atlantis hotel in the city as Mr Tabichi dedicated the award to his father, who raised him after his mother died when he was just 11.
Despite the grave obstacles Tabichi's students face, he's credited with helping many stay in school, qualify for global competitions in science and engineering and go on to college.
The students have hard experiences ranging from drug abuse, teenage pregnancies, early school dropout, young marriages and there have been cases of suicide.
Tabichi invited his father, who was in the audience, to the stage and handed the award for him to hold, to the applause and cheers of the room.
Kenyan President Uhuru Kenyatta said in a statement Mr Tabichi's story was "the story of Africa" and one of hope for future generations.
Last year, a British art teacher won the award for her work in one of the most ethnically diverse places in Britain.