More than £4m will be spent to raise standards in science and technology in Welsh schools.
It will be invested in a new national network which will see pupils work with universities and other experts.
Welsh students were below the average of 72 countries in science, reading and maths, it was revealed in a study.
Education Secretary Kirsty Williams said: “This new network of excellence is part of our national mission of education reform to raise standards.”
The Pisa results in December marked the fourth time Wales has done worse than other nations.
This planned network will pull together teaching practices for three to 18-year-olds, look at how other countries teach the subjects and allow schools to work together to develop courses and teaching.
Ms Williams added: “An understanding of science is crucial for our young people, from the technology they use, the way they communicate, through to the energy they use in a rapidly changing world.
“The science Pisa results chimed with our own understanding that we are not where we wish to be.
“This new network of excellence is part of our national mission of education reform to raise standards.”