The state border of Ukraine (Ukrainian: Державний кордон України, romanized: Derzhavnyi Kordon Ukrayiny; abbreviated as DerzhKordon) is the internationally recognized boundary of Ukraine, encompassing its land, maritime territory, and airspace. The border is jointly secured by the State Border Guard Service of Ukraine and the Armed Forces of Ukraine.

Ukraine shares land borders with seven countries: Belarus, Hungary, Moldova, Poland, Romania, Russia and Slovakia. These boundaries largely follow the demarcations established during the Soviet Union. The total length of Ukraine's international borders is 6,992.98 km (4,345.24 mi). The area of the exclusive economic zone of Ukraine is 72,658 km² (28,053 sq mi).

Ukraine's terrestrial borders span 5,637.98 km (3,503.28 mi). Below is a breakdown of its land boundaries with neighboring states:

Ukraine's southern maritime border follows the outer limits of its territorial waters in the Black Sea. It shares maritime boundaries with Romania and Russia, with additional interactions in contested regions.

The maritime border with Russia begins south of the Kerch Strait, where the Russian and Ukrainian EEZs meet. From there, it runs northward for 22.5 km (14.0 mi) through the strait, dividing territorial waters. The boundary continues into the Sea of Azov, designated as shared internal waters under a 2003 treaty, though this status is disputed following Russia's 2014 annexation of Crimea.

Within the Sea of Azov, the Russia–Ukraine maritime border spans 249.5 km (155.0 mi), extending to the northern coast where it meets the terrestrial border.

Ukraine's total maritime border measures 1,355 km (842 mi):

Disputes on the demarcation of borders with Russia, Belarus, and Moldova (formerly republics of the Soviet Union) are unresolved. The disputes with Russia and Belarus were further exacerbated with the start of the Russo-Ukrainian war.^{[citation needed]}