The contract, awarded to AECOM by the Ebbsfleet Development Corporation, is the first locally-led garden city to be developed in the UK in nearly a century.
The scheme was identified in the 2014 Budget, with government making available up to £200 million of infrastructure funding to kick start the development. It will provide up to 15,000 new homes across 1,026ha.
AECOM will lead a team comprising three sub-consultants: Stirling Prize winning architect Maccreanor Lavington, commercial property and real estate consultant Cushman & Wakefield, and Spacehub, a young design studio specialising in strategic landscape architecture, public realm and ecology.
Spacehub director Tom Smith said: "We are incredibly excited to be selected as part of the team to deliver the Ebbsfleet garden city masterplan. The project represents a unique opportunity to deliver the next chapter of the UK's garden city legacy. The masterplan will unlock an extraordinary landscape, reconnecting new and existing communities within Dartford, Gravesham and North West Kent."
AECOM's Andrew Jones said Ebbsfleet was the most significant strategic framework masterplan to be commissioned in the UK since the Olympic Park.
"As well as creating a new and distinctive community with excellent connections to London and Europe, the garden city will be a well-designed, self-sufficient settlement where people want to live, work and visit. As the first to come forward, Ebbsfleet must leave a legacy that will shape a generation of contemporary garden cities."
Work on the plan will start immediately, with the final framework masterplan due to be completed in 2016.