Live updates: follow the latest news on Russia-Ukraine
The meeting in Lithuania is part of the diplomatic response to the Ukraine crisis.
Ms Truss will use a speech alongside her fellow ministers to set out the UK’s support for Ukraine and demonstrate the unity of Nato.
“By continuing to respond with strength, united with our allies, we will ensure President Putin’s ambitions end in failure.”
Ms Truss will hold talks with Estonian foreign minister Eva-Maria Liimets, Latvia’s Edgars Rinkevics and Lithuania’s Gabrielius Landsbergis.
She will also meet UK military personnel from the Army Air Corps and 18 Squadron, Royal Air Force, who are currently deployed in Lithuania as part of a US-led exercise.
In other diplomatic efforts, Sports Secretary Nadine Dorries will join a virtual conference on Thursday with international counterparts to discuss banning Russian teams and individual athletes from international competition.
Along with ministers from the US, Australia, Germany and Poland, they will also discuss barring Russia and its ally Belarus from hosting any international sporting events.