In Spain, an autonomous community (Spanish: comunidad autónoma) is the first-level political and administrative division, created in accordance with the Spanish Constitution of 1978, with the aim of guaranteeing limited autonomy of the nationalities and regions that make up Spain.

Spain is not a federation, but a decentralised unitary country. While sovereignty is vested in the nation as a whole, represented in the central institutions of government, the nation has, in variable degrees, devolved power to the communities, which, in turn, exercise their right to self-government within the limits set forth in the constitution and their autonomous statutes. Each community has its own set of devolved powers; typically those communities with stronger local nationalism have more powers, and this type of devolution has been called asymmetrical. Some scholars have referred to the resulting system as a federal system in all but name, or a “federation without federalism”. There are 17 autonomous communities and two autonomous cities that are collectively known as “autonomies”. The two autonomous cities have the right to become autonomous communities, but neither has yet exercised it. This unique framework of territorial administration is known as the “State of Autonomies”.

The autonomous communities are governed according to the constitution and their own organic laws known as Statutes of Autonomy, which define the powers that they assume. Since devolution was intended to be asymmetrical in nature, the scope of powers (Spanish: competencia) varies for each community, but all have the same parliamentary structure; in fact, despite the Constitution not setting a mandatory legislative chamber framework, all autonomous communities have chosen unicameralism.