The deal has an option to extend to seven years and will include the enhancement of education, community, leisure and operational assets across the borough.
GRAHAM will now deliver both improvements and new build works as part of the council’s Capital Projects pipeline.
The first jobs will be two already approved leisure centre schemes and school developments.
Councillor Richard Cornelius, Leader of Barnet Council, said: “Barnet has a good track record of building major projects on time and on budget and this new partnership with Graham provides us further opportunity to deliver key buildings which will serve our residents for many years to come.”
Rod McMullan, GRAHAM Construction’s Director for the Partnership, said: ““We are looking forward to working with the council and the wider team to further improve the range and quality of council services and strengthen Barnet’s reputation as a thriving environment.”