A group of London boroughs under the PLACE (Pan-London Accommodation Collaborative Enterprise) banner awarded the deal.
Extraspace Solutions will design and manufacture 200 modular housing units by 2021.
Each which will have the quality of permanent housing with the additional benefit that they can be relocated to a different site when required so London boroughs can use them as temporary accommodation for homeless families.
Cllr Darren Rodwell, London Councils’ Executive member for housing and planning, said: “PLACE is an exciting new collaboration designed to secure more and better accommodation for homeless Londoners.
“The capital faces a worsening housing crisis. In response, the boroughs are joining forces to procure modular housing to use as temporary accommodation.
“PLACE will deliver high-quality, family-sized accommodation for homeless Londoners in their local borough – close to their schools, jobs, and support networks – and delivering new housing on previously unusable sites in the process.”
Eleanor Moloney, Extraspace Solutions Lead Designer, said: “We are thrilled to be helping to deliver this exciting initiative, showcasing modern modular solutions in the residential market.
“This scheme will combine innovative design with a community feel.
“Our precision-manufactured modular houses will deliver the quality of permanent homes, meeting the London Plan’s space standards, and can be relocated to the site of most need.”