Telford Homes has exchanged contracts for the site on International Way in Stratford E20 for £20m, subject to securing planning consent.
The land is being bought from London & Continental Railways (LCR), the Department for Transport and HS1 Ltd following a competitive process. It will be Telford Homes' third land acquisition from LCR.
The 1.14 acre site is expected to deliver approximately 380 homes, up to half of which will be subsidised affordable housing. The gross development value is expected to be in excess of £160.0 million.
Telford Homes specialises in brownfield developments in London at the less expensive end of the market. Chief executive Jon Di-Stefano said: "We have enjoyed considerable success in Stratford developing more than 1,750 homes in the area over the last 12 years. This site is really well located next to the International station and Westfield, and is an excellent addition to our development pipeline."