The Crown is a political concept used in Commonwealth realms, analogous to the concept of the state in legal systems influenced by Roman civil law.

English common law never developed a concept of the state and left supreme executive power with the king. The concept of the Crown as a corporation sole developed in the Kingdom of England as a separation of the physical crown and property of the kingdom from the person and personal property of the monarch. It spread through English and later British colonisation, becoming embedded in the legal lexicon of the British dominions. As the dominions gained control over the royal prerogative in the 1930s, the concept evolved such that 'the Crown in right of' each realm and territory acts independently of the other realms and territories.

Depending on the context used, it may refer to the entirety of the state, the executive government specifically (either of a realm or one of its provinces, states or territories) or only to the monarch and their direct representatives. As a political concept, the Crown should not to be confused with any physical crown, such as those of the British regalia.

The term the Crown does not have a single definition. Legal scholars Maurice Sunkin and Sebastian Payne opined, "the nature of the Crown has been taken for granted, in part because it is fundamental and, in part, because many academics have no idea what the term the Crown amounts to". Nicholas Browne-Wilkinson theorised that the Crown is "an amorphous, abstract concept" and, thus, "impossible to define", while William Wade stated the Crown "means simply the Queen".

Warren J. Newman described the Crown as "a useful and convenient means of conveying, in a word, the compendious formal, executive and administrative powers and apparatus attendant upon the modern constitutional and monarchical state."

Lord Simon of Glaisdale stated:

The crown as an object is a piece of jewelled headgear under guard at the Tower of London. But it symbolizes the powers of government which were formerly wielded by the wearer of the crown ... The term "the Crown" is therefore used in constitutional law to denote the collection of such of those powers as remain extant (the royal prerogative), together with such other powers as have been expressly conferred by statute on "the Crown".

Lord Diplock suggested the Crown means "the government [and] all of the ministers and parliamentary secretaries under whose direction the administrative work of the government is carried out by the civil servants employed in the various government departments." This interpretation was supported by section 8 of the Pensions (Colonial Service) Act 1887 (50 & 51 Vict. c. 13), which set the terms "permanent civil service of the state", "permanent civil service of Her Majesty" and "permanent civil service of the Crown" as having the same meaning.