A self-governing colony is a colony with an elected legislature, in which politicians are able to make most decisions without reference to the colonial power with formal or nominal control of the colony. In almost all cases self-governing colonies have responsible government.

The term is most often used for British overseas territories (formerly known as crown colonies), in the Commonwealth, formerly the British Empire. Historically, the status of self-governing colony has often represented a transitional stage between between direct rule from the United Kingdom and full independence.

While the legislatures of British self-governing colonies — for the most part — control their internal affairs, the British government retains control of foreign affairs, defence and various international trade matters. The British government is represented in self-governing colonies by a Governor, who exercises some degree of control over affairs of state. The Governor appoints a cabinet with executive power from the majority party in the legislature, which is led by a Chief Minister or Premier.

The term "self-governing colony" has sometimes been used in relation to the direct rule of a Crown Colony by an executive governor , elected under a limited franchise, such as in Massachusetts between 1630 and 1684.

In the modern sense of the term, the first self-governing colony is generally considered to have been the Province of Canada, from 1841; the colony gained responsible government in 1848, followed in 1867 by federation with other colonies and dominion status. However, the term "self-governing colony" is not widely used by Canadian constitutional experts. The term is widely used in relation to the political arrangements in the seven British settler colonies of Australasia between 1852 and 1907.

The best-known examples of self-governing colonies are the Dominions, during the mid-to-late-19th century and early 20th century. In the Dominions, prior to the Statute of Westminster in 1931, a Governor General, officially the monarch's representative, was a de facto arm of the British government.

After the passing of the Statute of Westminster, the Dominions ceased to be considered colonies, although many colonies which did not have Dominion status were also self-governing. However, after that time, the Dominions were largely free to act in matters of defence and foreign affairs, if they so chose and "Dominion" gradually acquired a new meaning: a state which was independent of Britain, but which shared the British monarch as the official head of state. The term Dominion has largely fallen out of use and been replaced with the term Commonwealth realm.

Colonies are sometimes referred to as "self-governing" in situations where the executive is controlled neither by the imperial government nor a local legislature, but by a local oligarchy. However, since the mid-19th century, if the government of a colony is not under the formal control of the imperial authorities, it will be considered to be subject to the formal control of the local legislature.

Self-governing colonies for the most part have no formal authority over constitutional matters such the monarchy and the constitutional relationship with Britain. They utilise appeals to the Judicial Committee of the Privy Council, in London, as the ultimate avenue of appeal in matters of law and justice.

By 2005, the only self-governing colonies under the above definition are: Anguilla, Bermuda, British Virgin Islands, Montserrat, Gibraltar, and Turks and Caicos Islands. All other British overseas territories experience greater degrees of control over their affairs by the UK government.