A quarter of all Londoners have offered a bed to a homeless friend or family member.
According to a YouGov survey, 25% of people in the Capital have hosted a relation or acquaintance in need of accommodation.
The research also says that approximately 110,000 households have someone staying with them who would otherwise be homeless.
Green Party London Assembly Member Sian Berry, who commissioned the research, said: “No one in London is oblivious to the crisis we have in our city when it comes to enough homes, decent homes and affordable homes.
“We have a particular problem in London and no one is immune to having to rely on a friend’s spare room or sofa for somewhere to sleep.”
Ms Berry also called on Mayor of London Sadiq Khan and the government to make sure councils have the resources they need to help prevent homelessness.
“It should not be left to Londoners to make up for failings in our ability to provide homes for our citizens, many of whom are already living in overcrowded conditions.”