The Tories were a loosely organised political faction and later a political party, in the Parliaments of England, Scotland, Ireland, Great Britain and the United Kingdom. They first emerged during the 1679 Exclusion Crisis, when they opposed Whig efforts to exclude James, Duke of York from the succession on the grounds of his Catholicism. Despite their fervent opposition to state-sponsored Catholicism, Tories opposed his exclusion because of their belief that inheritance based on birth was the foundation of a stable society.

After the succession of George I in 1714, the Tories had no part in government. They ceased to exist as an organised political entity in the early 1760s; however, the term continued to be used in subsequent years as a term of self-description by some political writers. About 20 years later, a new Tory party arose and participated in government between 1783 and 1830, with William Pitt the Younger followed by Robert Jenkinson, 2nd Earl of Liverpool. The Whigs won control of Parliament in the 1831 election, which was fought largely on the issue of electoral reform, opposed by the Tories. The Representation of the People Act 1832 removed the rotten boroughs, many of which were controlled by Tories and the Party was reduced to 175 MPs in the 1832 elections.

Under the leadership of Robert Peel, who issued a policy document known as the Tamworth Manifesto, the Tories began to transform into the Conservative Party. However, his repeal of the Corn Laws in 1846 caused the party to break apart; the faction led by the Earl of Derby and Benjamin Disraeli went on to become the modern Conservative Party, whose members are still commonly referred to as Tories.

As a political term, Tory was an insult (derived from the Middle Irish word tóraidhe, modern Irish tóraí, meaning "outlaw", "robber", from the Irish word tóir, meaning "pursuit" since outlaws were "pursued men") that entered English politics during the Exclusion Bill crisis of 1678–1681. Whig (from whiggamore, a "cattle driver") was initially a Scottish insult for the Covenanter faction in Scotland who opposed the Engagers (a faction who supported Charles I during the Second English Civil War) and supported the Whiggamore Raid that took place in September 1648. While the Whigs were those who supported the exclusion of James, the Duke of York from the succession to thrones of Scotland, England and Ireland (the Petitioners), the Tories were those who opposed the Exclusion Bill (the Abhorrers).

In 1757, David Hume wrote:

The court party reproached their antagonists with their affinity to the fanatical conventiclers in Scotland, who were known by the name of Whigs: The country party found a resemblance between the courtiers and the popish banditti in Ireland, to whom the appellation of Tory was affixed. And after this manner, these foolish terms of reproach came into public and general use; and even at present seem not nearer their end than when they were first invented.

The first Tory party traces its principles and politics to the English Civil War which divided England between the Cavaliers (supporters of King Charles I) and the Roundheads (the supporters of the Long Parliament upon which the King had declared war). This action resulted from the Parliament not allowing him to levy taxes without yielding to its terms. At the beginning of the Long Parliament (1641), the King's supporters pursued a course of reform of previous abuses. The increasing radicalism of the Parliamentary majority, however, estranged many reformers even in the Parliament itself and drove them to make common cause with the King. The King's party was thus a mixture of supporters of royal autocracy and of those Parliamentarians who felt that the Long Parliament had gone too far in attempting to gain executive power for itself and, more specifically, in undermining the episcopalian government of the Church of England, which was felt to be a primary support of royal government. By the end of the 1640s, the radical Parliamentary programme had become clear: reduction of the King to a powerless figurehead and replacement of Anglican episcopacy with a form of Presbyterianism.

This prospective form of settlement was prevented by a coup d'état which shifted power from Parliament itself to the Parliamentary New Model Army, controlled by Oliver Cromwell. The Army had King Charles I executed and for the next 11 years the British kingdoms operated under military dictatorship. The Restoration of King Charles II produced a reaction in which the King regained a large part of the power held by his father. However, Charles' ministers and supporters in England accepted a substantial role for Parliament in the government of the kingdoms. No subsequent British monarch would attempt to rule without Parliament, and after the Glorious Revolution of 1688, political disputes would be resolved through elections and parliamentary manoeuvring, rather than by an appeal to force. Charles II also restored episcopacy in the Church of England. His first Cavalier Parliament began as a strongly royalist body, and passed a series of acts re-establishing the Church by law and strongly punishing dissent by both Roman Catholics and non-Anglican Protestants. These acts did not reflect the King's personal views and demonstrated the existence of a Royalist ideology beyond mere subservience to the Court.