It has formed a 50:50 partnership with Oxford University to deliver the programme over the next 10 years.
The deal unlocks plans to redevelop five sites in and around Oxford.
These include building 2,000 homes on green belt land at Begbroke, near Kidlington, with around half set aside for junior academic and non-academic staff.
A further 500 new student homes and a science park is earmarked for Osney Mead, while in Iffley, semi-detached houses will be demolished and replaced with more student accommodation.
Projects are also planned for Jericho and Summertown.
The University entered into the development deal because of concerns that lack of affordable residential and commercial space was constraining its growth in student numbers and science start-up businesses.
Professor Louise Richardson, Vice-Chancellor of the University of Oxford, said: “We will build much-needed graduate accommodation, subsidized housing for University staff, and new science parks, where academic departments, University spin-outs and commercial partners can work together to create new companies as well as high quality jobs.”
John Cummins, Managing Director of Legal & General’s Future Cities Business, said: “This partnership is a unique opportunity for two large and long-term UK institutions to work together to address Oxford University’s, and indeed the city’s, future needs, enabling it to continue to be a centre of growth.”
Legal & General’s Future Cities business has already funded the creation of over 2.5m sqft of commercial space, over a thousand new homes and tens of thousands of jobs, in cities such as Cardiff, Leeds, Manchester, Newcastle and Salford.