A landlocked state or country is a sovereign state entirely enclosed by land, or whose only coastlines lie on closed seas. There are currently 48 such countries, including four partially recognised states. Only two, Bolivia and Paraguay in South America, lie outside Afro-Eurasia (the Old World).

As a rule, being landlocked creates political and economic handicaps that access to the high seas avoids. For this reason, states large and small across history have striven to gain access to open waters, even at great expense in wealth, bloodshed, and political capital.

Depending on degree of development, language barriers, and other considerations, being landlocked may or may not pose economic disadvantages. Some historically landlocked countries are quite affluent, such as Switzerland, Luxembourg, and Liechtenstein, all of which frequently employ neutrality to their political advantage. The majority, however, are classified as Landlocked Developing Countries (LLDCs). Nine of the twelve countries with the lowest Human Development Indices (HDI) are landlocked.