A spokeswoman for Lithuanian President Dalia Grybauskaite confirmed the trip to the Baltic News agency in the country's capital Vilnius.
She said: "In principle, we have the decision, we've heard it. Officially it will be announced in December.
"The occasion is beautiful because the Baltic States will celebrate the centenary."
She added that the visit is scheduled for autumn of 2018 but the Vatican is yet to announce the exact dates for the trip.
It will be the pontiff's first visit to the Baltic nations since his election over four years ago but the second time a pope has visited.
Pope John Paul II visited all three Baltic states in 1993.
More than 75 per cent of the nation's nearly 3 million inhabitants are Catholics.
The three Baltic nations declared their independence from Russia in 1918 but were incorporated into the Soviet Union in 1940 and remained part of it until 1991.
