Legal tender is defined as the accepted medium of exchange to settle a public or private debt. The national currency is considered legal tender in almost every country in the world and the primary medium of exchange for most countries. Legal tender is determined by government statute and its manufacture/creation is strictly controlled.

Many governments have not explicitly defined cryptocurrencies whether cryptocurrencies are legal tender. Regarding the tax treatment for cryptocurrencies, many tax authorities have defined cryptocurrencies as capital assets.

As online commerce continues to grow and more merchants continue to use cryptocurrencies as a payment option, the market (although not officially endorsed by any government institution) does treat cryptocurrency as legal tender.

As we continue to move into the digital age, its likely governments will adopt the technology and protocols used by cryptocurrencies, which may lead to the creation of the government's own cryptocurrency.

Launched in February 2018, the Petro, a centrally controlled cryptocurrency developed and issued by the government of Venezuela. The Republic of the Marshall Islands (RMI) also has announced it would adopt its own sovereign cryptocurrency as legal tender.

On June 2021, the president of El Salvador proposed to use Bitcoin as legal tender. The U.S. dollar is currently El Salvador's official currency.