A court of equity, also known as an equity court or chancery court, is a court authorized to apply principles of equity rather than principles of law to cases brought before it. These courts originated from petitions to the Lord Chancellor of England and primarily heard claims for relief other than damages, such as specific performance and extraordinary writs. Over time, most equity courts merged with courts of law, and the adoption of various Acts granted courts combined jurisdiction to administer common law and equity concurrently. Courts of equity are now recognized for complementing the common law by addressing its shortcomings and promoting justice.

In the early years of the United States, some states followed the English tradition of maintaining separate courts for law and equity. Others combined both types of jurisdiction in their courts, as the US Congress did for federal courts. United States bankruptcy courts serve as an example of a US federal court that operates as a court of equity. A few common law jurisdictions, such as the U.S. states of Delaware, Mississippi, New Jersey, South Carolina, and Tennessee, continue to preserve the distinctions between law and equity as well as between courts of law and courts of equity. In New Jersey, this distinction is upheld between the civil and general equity divisions of the New Jersey Superior Court.

The unique nature of courts of equity is a result of their historical evolution. This history has been crucial in shaping their application in case law, reflecting the values that have developed the equitable jurisdiction. The transformation of these courts demonstrates the evolution of equity's doctrines and remedies, changes in its dominant nature and traits, and the influence of social and political environments on its operation and underlying issues in jurisprudence.

Equity is currently recognized as a distinct body of law, administered by various modern courts. The evolution of procedures within courts of equity has guided the application of equitable principles. Originating from the diverse rules of the early Courts of Chancery, today's courts can exercise equitable jurisdiction while maintaining their inherent discretionary abilities to address new forms of injustice. Equity is not an independent body of law; rather, it is synonymous with corrective justice and complements common law to counterbalance its inflexible rules.

The historical emergence of equity occurred during three significant periods: the medieval period (13th–15th centuries), the formative period (16th–17th centuries), and the period of systematization (17th–19th centuries). Throughout these periods, equity developed progressively from the Chancellor providing equitable relief based on personal conscience to an established and organized body of law governed by courts.

The Chancery Division was established in the 13th century by the King after the separation of the Supreme Court of Judicature. Under the Chancellor's authority, the "King's law" prevailed in local courts. The division did not handle actual cases but performed functions associated with the King's secretarial department. Although the Chancery Division did not function as a court, judicial activity was still present. Limited discretionary power was provided, determining the validity of writs issued in courts and permitting only those in consimili casu. These were enforced temporarily and could be overridden by the courts of law if deemed to conflict with the actual law of the land. As the administrative operations of the division expanded through its implicit control of the King's residual influence, the Chancellor became responsible for addressing "prayers" and "petitions", including letters of remedy, relief, and grants on behalf of the King. During the 14th and 15th centuries, the Chancery developed into an independent and extensive bureaucracy. Its formalized role involved issuing writs regarding inheritance or property transfers, which served as the justice's authorization for initiating claims in the King's courts.

In the 16th century, the modern system of equity and the Chancellor evolved into a body with recognized judicial features. Consequently, the jurisdiction within the courts experienced greater autonomy. This involved the Court of Chancery issuing decrees independently of the King's Council, the Chancellors becoming proficient in law, and a more systematized role in resolving petitions. As it developed into a substantive judicial court with increased power, other common law courts became wary and defensive towards their jurisdiction. The court was one of specific jurisdiction with distinct procedures compared to common law courts, such as the Court of Chancery issuing a common injunction rather than common law injunctive relief.

The systemisation of equity is often credited to Lord Eldon and the introduction of the Judicature Acts in 1873. He rationalized the rules and principles found in modern equity today, to provide enhanced consistency and certainty. As a result, equity existed in conjunction with the common law. Prior to this, the Courts of Chancery experienced shortcomings and a "period of decline and stagnation" during the early 18th century. Such defects included jurisdictional delays, administrative complications, costly proceedings and burdensome processes.