According to the Chinese company's first quarter results, it has 340 million active monthly users, 30% up on the previous year.
About 154 million people use the site daily, 91% of whom access it via mobile.
By comparison, Twitter, which is blocked in China, has around 328 million active monthly users.
"Our relentless focus to build the best social media experience in China is reflected in Weibo's strong performance," Gaofei Wang, Weibo chief executive, said in a statement.
