BAM Construction will be responsible for the construction of a £46m campus in Peebles, replacing the High School that was damaged in a fire in late 2019.
Morrison Construction, part of Galliford Try, has been handed a £55m contract to deliver the Galashiels Community Campus, a replacement for the old Galashiels Academy building.
Hub South East will oversee both projects through the various development phases as Borders Council's development partner.
Planning applications are scheduled to be submitted next year. A period of further design development for the projects will then follow with construction works expected to start at both sites in late 2022.
Councillor Carol Hamilton, executive member for children and young people at Scottish Borders Council, said: “The appointments of BAM Construction and Morrison Construction as tier one contractors and the announcement of our continued partnership with Hub South East marks an important step in the progression of these two major projects.
“We believe their respective track records in successfully delivering projects of this scale can help the council achieve its ambition of providing world-class education facilities for young learners across the Borders.”