The report by eMarketer forecasts that Twitter's global user base will increase 24.4 percent in 2014, led by big gains in countries such as Indonesia and India, and to a lesser extent Argentina, Mexico and Brazil.
The research firm said its figures on current Twitter usage are lower than company estimates 183 million at the end of 2013 "because we rely heavily on consumer survey data to weed out business accounts, multiple accounts for individual users and other sources of potential double-counting."
Twitter in April estimated the monthly active users at 255 million, which led to a slump in its share price because it suggested sluggish growth.
The eMarketer report said Twitter's worldwide users will hit 227 million this year, and nearly 400 million by 2018.
In its analysis of worldwide users, eMarketer said the Asia-Pacific region had already overtaken North America with more than 30 percent of all Twitter users.
And the figures exclude China, which bans the US messaging service.
"In 2014, the Asia-Pacific region will account for 32.8 percent of all Twitter users, compared with 23.7 percent in North America," the report said.
"And by 2018, Asia-Pacific will more than double North America's share, breaking the 40 percent mark in terms of worldwide market share. If China is on the Twitter map by that point, that share is likely to be significantly higher."
The research said Twitter user growth in the US "is maturing" and will taper off into single digits by 2015.
"Twitter's US user base gets outsize but appropriate attention because it accounted for nearly three-quarters of Twitter's total ad revenues in 2013, according to company reports," said eMarketer.
"The US will remain the single largest country in terms of the number of individual Twitter users throughout our forecast, but currently, it still represents just over 20 percent of all Twitter users worldwide."