The Land Forces are the land forces of the Polish Armed Forces. They currently contain some 100,000 active personnel and form many components of the European Union and NATO deployments around the world. Poland's recorded military history stretches back a millennium – since the 10th century. Poland's modern army was formed after Poland regained independence following World War I in 1918.

The Polish–Lithuanian War was an undeclared war between newly independent Lithuania and Poland following World War I, which happened mainly in the Vilnius and Suwałki regions. The war is viewed differently by the respective sides. According to Lithuanian historians, it was part of the Lithuanian Wars of Independence and lasted from May 1919 to 29 November 1920. Polish historians deem the Polish–Lithuanian war as occurring only in September–October 1920. Since the spring of 1920, the conflict became part of the wider Polish–Soviet War and was largely shaped by its progress. It was subject to international mediation at the Conference of Ambassadors and the League of Nations.