Contractor Leadbitter will start work on Hampton Academy shortly and then start Twickenham Academy in the summer.
Hampton Academy, formally Hampton Community College, will receive a £16m in Government funding to pay for the demolition and rebuilding of a number of buildings on the site.
A further £22m will be spent on demolishing Whitton School to make way for the new Twickenham Academy.
Both academies are run by the Learning Schools Trust and are sponsored by Swedish education company Kunskapsskolan.