There were 2,325 Vietnamese out of a total of 3,438 foreign nationals granted Taiwanese citizenship, according to statistics released by the Taiwanese Ministry of Interior.
The Philippines with 362 and Indonesia with 350 followed.
Getting married to Taiwanese citizens was the top reason for naturalization, accounting for 86.1 percent of all cases.
Women accounted for 3,097 of the new citizens.
Vietnamese women getting married to Taiwanese men accounted for more than 73 percent of the 2,794 brides who were naturalized.