Statute of Westminster 1931

The Statute of Westminster 1931 (22 & 23 Geo. 5. c. 4) is an act of the Parliament of the United Kingdom that significantly increased the autonomy of the Dominions of the British Commonwealth.

Passed on 11 December 1931, the statute increased the sovereignty of the self-governing Dominions of the British Empire from the United Kingdom. It also bound them all to seek each other's approval for changes to monarchical titles and the common line of succession. The statute was effective either immediately or upon ratification. It thus became a statutory embodiment of the principles of equality and common allegiance to the Crown set out in the Balfour Declaration of 1926. As the statute removed nearly all of the British parliament's authority to legislate for the Dominions, it was a crucial step in the development of the Dominions as separate, independent, and sovereign states.

Its modified versions are now domestic law in Australia and Canada (including Newfoundland and Labrador). It is no longer in effect in New Zealand, and has been implicitly repealed in former Dominions that are no longer Commonwealth realms.