Self-Defence of Lithuania and Belarus () were voluntary military formations created during the reconstitution of sovereign Poland towards the end of World War I in the Kresy macroregion, formerly the Western Krai of the Russian Empire. Self-Defence units were composed mostly of Poles loyal to the nascent Second Polish Republic, formed after a century of Partitions.
Organizations for the Defence of Lithuania and Belarus () were volunteer military groups created during Poland's revival as an independent state in the aftermath of World War I in the Kresy area, previously part of the Russian Empire. The Self-Defence units mainly comprised Poles who were committed to the newly formed Second Polish Republic, which had been established after a century of foreign domination.