英联邦王国（英语：Commonwealth realm）是英联邦之**戴同一位君主为君主立宪制国家元首的独立国家。目前共有16个英联邦王国，而这些国家的国家元首同为伊莉莎白二世女王。英联邦王国互不隶属，但一起构成迄今为止世界上现存最大的一个共主邦联，而每个英联邦王国也分别是英联邦范围内的主权国家。2010年，这16国领土面积总合约1870万平方公里，人口数共约1.34亿。女王在各个英联邦王国之中，也有相应不同的称号，例如在英国称为「蒙上帝恩典，大不列颠及北爱尔兰联合王国与其属土及领地之女王，英联邦元首，信仰的保护者」，而在巴巴多斯的称号则为「蒙上帝恩典，巴巴多斯女王，英联邦元首」。

A Commonwealth realm is one of 16 sovereign states that are members of the Commonwealth of Nations, have Queen Elizabeth II as the reigning constitutional monarch, and have in common the same royal line of succession.

The Statute of Westminster 1931 provided for the then Dominions—named therein as Canada, Australia, New Zealand, the Union of South Africa, the Irish Free State, and Newfoundland—to have full or nearly full legislative independence as equal members of the British Commonwealth of Nations, having with the United Kingdom one person as the sovereign of each respectively. Thereafter, India and Pakistan in 1947 and Ceylon in 1948 became Dominions. By the early 1950s, in order to reflect the equality between the countries in that group, each (including the United Kingdom, but not the former Irish Free State and India, which had by that time become republics) came to be known as a realm. The term was formally used with Britain's proclamation of Elizabeth II as queen in 1952 and was adopted for the modern royal styles and titles under the legislation enacted by the individual countries. The phrase Commonwealth realm is only an informal description, not an official term. The sovereign status of other Commonwealth realms was later granted directly.