About three quarters of Londoners think an average-sized three-bedroom family home is out of their financial reach, a study by charity Shelter found.
The survey of 2,000 people showed 76% of people living in the UK capital thought it would be out of their price range, compared to 61% nationally.
A quarter of Londoners said they would move to an area where property cost less if their family grew.
Only in northern Scotland did 51% think they could afford a house of that size.
Shelter Director Adam Sampson said: "Londoners are bearing the brunt of Britain's affordability crisis.
"The capital's property escalator means the average three bedroom home - the heart of family life - is now a thing of the past for people on a normal income.
"And it's children who are hit hardest, by being forced to leave their school behind and start their education afresh in a new area where their family can afford to live."