A further 20% did not think the UK should remain in the EU, and 19% had no definitive opinion about the issue.
TNS ran the poll online February 23-25, interviewing 1,000 working-age residents of Latvia.
EU leaders have reached a deal on the bloc’s reforms with UK Prime Minister David Cameron.
The deal increases the hope that in the June 23 referendum on the UK’s possible exit from the EU will result in the country staying in the bloc.