The contract involves Lovell delivering planned refurbishment and electrical work across a portfolio of 15,000 homes.
Barnet Homes manages and maintains homes and estates on behalf of Barnet Council.
Work is set to start in April 2012.
Morgan Sindall Group chief executive Paul Smith said: "This is another important win for Lovell which builds on the response maintenance work we acquired as part of the acquisition from the administrators of Connaught. Today's announcement underlines our leading position in affordable housing. Lovell's full service offering will mean we can deliver the highest quality upgrade and response maintenance work to the Barnet Council housing stock."