Latvia and Estonia are also expelling three Russian diplomats each.
Lithuania made the decision "in solidarity with Ukraine, which has been facing the unprecedented Russian military aggression", the ministry said.
Russia's Ambassador to Lithuania Alexey Isakov was summoned to the Ministry of Foreign Affairs today and was handed a diplomatic note, declaring four employees of the Russian Embassy to be undesirable persons in Lithuania for activities incompatible with their diplomatic status. They were told to leave Lithuanian within five days.
"Lithuania condemned Russia's military invasion of this country and expressed full support for Ukraine, which is currently fighting the brutal war that the Russian regime is waging against this sovereign state," the ministry said in a statement.
"Russian special services are actively involved in organizing and carrying out the military invasion against Ukraine, posing threat not only to Ukraine's, but also Lithuania's security," the statement reads.
Lithuania calls on Russia to respect international law, abandon the heinous war and further civilian suffering, as well as to withdraw its occupying forces from the entire territory of Ukraine.
Also on Friday, Latvia's Foreign Ministry said it was sending three Russian diplomats out of the country, declared undesirable persons.
"Current activities of those persons under diplomatic cover are incompatible with their diplomatic status and are causing detriment to the Republic of Latvia," the ministry said.
The Estonian Ministry of Foreign Affairs summoned the Russian ambassador to Estonia and handed over a diplomatic note stating that three staff members with the diplomatic status of the Russian Embassy have been declared persona non grata.
Earlier in the day, Bulgaria also announced its decision to expel ten Russian diplomats.