Trying to quit on their own proved much more difficult - 17 per cent of those whose partners were already non-smokers succeeded, and just eight per cent of those whose partners were unreformed regular smokers.
"Now is the time to make New Year's resolutions to quit smoking, take exercise, or lose weight," said lead researcher Dr Sarah Jackson, from University College London.
"And doing it with your partner increases your chances of success."
The study, published in the journal Jama Internal Medicine, was funded by Cancer Research UK, the British Heart Foundation, and the US National Institute on Aging.