Lithuania–Poland relations

Poland and Lithuania established diplomatic relations from the 13th century, after the Grand Duchy of Lithuania under king Mindaugas acquired some of the territory of Rus' and thus established a border with the then-fragmented Kingdom of Poland. Polish–Lithuanian relations subsequently improved, ultimately leading to a personal union between the two states. From the mid-16th to the late 18th century Poland and Lithuania merged to form the Polish–Lithuanian Commonwealth, a state that was dissolved following their partition by Austria, Prussia and Russia. After the two states regained independence following the First World War, Polish–Lithuanian relations steadily worsened due to rising nationalist sentiments. Competing claims to the Vilnius region led to armed conflict and deteriorating relations in the interwar period. During the Second World War Polish and Lithuanian territories were occupied by both the Soviet Union and Nazi Germany, but relations between Poles and Lithuanians remained hostile. Following the end of World War II, both Poland and Lithuania found themselves in the Eastern Bloc, Poland as a Soviet satellite state, Lithuania as a Soviet republic. With the fall of communism relations between the two countries were reestablished. Since then relations have been friendly and akin to strategic partnership in defence and security.

The two countries became members of the European Union in 2004.