The Treasury committee has criticised several areas of the Chancellor's Right to Buy plans in a report on his latest Budget.
The intervention in the housing market may not even help first time buyers - the group the Government insists it is keen to support, MPs said.
They also said Mr Osborne's claim that increased demand will boost supply is "unconvincing".
MPs added that they "struggle to see the rationale for the taxpayer to stand behind loans for people wishing to own a second property".
The committee also warned the Government will come under "immense" pressure to extend Help to Buy in three years time, despite its status as "a scheme designed to deal with a supposedly temporary problem".
More top news
Anger at the verdict in the shooting of black teenager Michael Brown has left the US deeply divided during its celebration of togetherness.
For most of the country, tomorrow is set to get off to a more pleasant start as it should be drier and brighter with the odd sunny spell.
A man who was abused by John Allen as a child has spoken out as the former care home boss has been found guilty of a further eight charges.