From mid-June councils will have powers to issue penalty charge notices to the registered owner of a car, regardless of who littered.
CCTV images will be used to record number plates and trace owners, said London Councils.
The AA said the majority of its members wanted tougher penalties for people who drop litter from cars.
Littering is already a criminal offence which incurs a fine, under the Environmental Protection Act.
To prosecute someone for littering from a car required proving beyond reasonable doubt which passenger disposed of the rubbish, which is very difficult, said a spokesman for London Councils.
But the organisation which represents London's 33 councils put a private bill through Parliament to amend the London Local Authorities Act so that the owner of a vehicle or pedicab will be liable to pay littering fines.
Council officers and Police Community Support Officers will be among those who can issue penalties, said London Councils.
The exact level of fine will be decided on 14 June and the new law should come into effect on 18 June.
An AA spokesman said the organisation's research suggests the majority of drivers in London and Britain would like greater penalties for littering from cars.
In a survey of 1,628 AA members in London in 2009, 58% said they loathed motoring "litter louts" enough to support tough penalties, such as points on their driving licence, large fines and community sentences.
Ninety-three percent agreed that roadside litter gave a bad impression of Britain and spoilt local communities.
Seven per cent admitted littering.
He said: "A cigarette thrown from a car will spark and make a driver jump. Similarly a container coming at your windscreen will make you duck."
But he pointed out that enforcement will be an issue and there will be cases where items are dropped accidentally.
He said: "In amongst rubbish you will always find a baby's dummy and know that it's unlikely that its mother wanted that littered.
"What happens if a six-year-old opens the back door, drops something and walks off? That could be littering."
Car owners in London will face fines of up to £100 if someone drops litter from their vehicles, under a law change.