Of the 18-to-24-year-olds surveyed, 28% cited social media as their main news source, compared with 24% for TV.
The Reuters Institute for the Study of Journalism research also suggests 51% of people with online access use social media as a news source.
This trend and the rising use of mobile phones to access news are undermining traditional business models.
The report, now in its fifth year, is based on a YouGov survey of about 50,000 people across 26 countries, including 2,000 Britons.
