YouGov surveyed 2061 adults in Britain and found 30% of those surveyed bet with SkyBet during the tournament.
Paddy Power was the second most popular site with 24%, followed by Bet365 with 22%, Betfair with 18%, William Hill with 17% and Ladbrokes with 16%.
The research also found 14% of people took part in a World Cup sweepstake with family, friends or in the workplace.
According to the research, more than three times as many bets were placed online than via land-based operators.
The YouGov data also suggests about one sixth of these people were new gamblers who looked to take advantage of introductory offers offered to new customers; one third of the bettors opened up a new account to take advantage of these offers.
