Poroshenko is scheduled to meet on Friday with Lithuanian President Dalia Grybauskaitė, Viktoras Pranckietis, the speaker of the Seimas, and Prime Minister Saulius Skvernelis.
Bilateral meetings between the presidents of Lithuania and Ukraine are traditionally held once a year.
As part of the meeting, the energy ministers of the two countries plan to sign a memorandum under which Lithuanian experts will go to Ukraine to share their experience in closing down the Ignalina nuclear power plant.
The Lithuanian government decided on the eve of the visit to hand over seven ground transmitters to Ukraine for broadcasts to areas controlled by Russia-backed separatists.
Poroshenko's visit to Lithuania comes at a time of increased tensions in Ukraine after law-enforcement authorities tried to arrest former Georgian President Mikheil Saakashvili on charges of financial crimes, but he was freed by his supporters.
The Ukrainian president also faces increasing pressure from the West due to insufficient anti-corruption efforts. The focus of attention this week was on attempts by Ukrainian parliamentarians and influential law-enforcement officials to weaken the National Anti-corruption Bureau of Ukraine.