A non-sovereign monarchy, subnational monarchy or constituent monarchy is one in which the head of the monarchical polity (whether a geographic territory or an ethnic group), and the polity itself, are subject to a temporal authority higher than their own. The constituent states of the German Empire or the princely states of the Indian Empire during British rule provide historical examples; while the Zulu king, whose power derives from the Constitution of South Africa, is a contemporary one.

This situation can exist in a formal capacity, such as in the United Arab Emirates (in which seven historically independent emirates now serve as constituent states of a federation, the president of which is chosen from among the emirs), or in a more informal one, in which theoretically independent territories are in feudal suzerainty to stronger neighbors or foreign powers (the position of the princely states of India during British rule), and thus can be said to lack sovereignty in the sense that they cannot, for practical purposes, conduct their affairs of state unhampered. The most formalized arrangement is known as a federal monarchy, in which the relationship between smaller constituent monarchies and the central government (which may or may not have a territory of its own) parallels that of states to a federal government in republics, such as the United States of America. Like sovereign monarchies, there exist both hereditary and elective non-sovereigns.

Systems of both formal and informal suzerainty were common before the 20th century, when monarchical systems were used by most states often originating from the feudal fiefdoms of the Middle Ages. During the last century, however, many monarchies have become republics, and those who remain are generally the formal sovereigns of their nations. Sub-national monarchies also exist in a few states which are, in and of themselves, not monarchical, (generally for the purpose of fostering national traditions).

The degree to which the monarchs have control over their polities varies greatly—in some they may have a great degree of domestic authority (as in the United Arab Emirates), while others have little or no policy-making power (the case with numerous ethnic monarchs today). In some, the monarch's position might be purely traditional or cultural in nature, without any formal constitutional authority at all.

Wallis and Futuna is an overseas collectivity of the French Republic in Polynesia consisting of three main islands (Wallis, Futuna, and the mostly uninhabited Alofi) and a number of tiny islets. The collectivity is made up of three traditional kingdoms: Uvea, on the island of Wallis, Sigave, on the western part of the island of Futuna, and Alo, on the island of Alofi and on the eastern part of the island of Futuna. The current co-claimants to the title King of Uvea are Felice Tominiko Halagahu and Patalione Kanimoa, the current King of Alo is Filipo Katoa and the current King of Sigave is Eufenio Takala. They have been reigning since 2016.

The territory was annexed by the French Republic in 1888, and was placed under the authority of another French colony, New Caledonia. The inhabitants of the islands voted in a 1959 referendum to become an overseas collectivity of France, effective in 1961. The collectivity is governed as a parliamentary republic in which the citizens elect a Territorial Assembly, the president of which becomes the head of government. His cabinet, the Council of the Territory, is made up of the three kings and three appointed ministers. In addition to this limited parliamentary role the kings play, the individual kingdoms' customary legal systems have some jurisdiction in areas of civil law.

A number of independent Muslim sultanates and tribal territories existed in the East Indies (the modern-day states of Malaysia, Indonesia, Singapore, and Brunei) before the coming of colonial powers in the 16th century, the most prominent one in what is now Malaysia being Melaka. The first to establish colonies were the Portuguese, but they were eventually displaced by the more powerful Dutch and British. The 1824 Anglo-Dutch Treaty defined the borders between British possessions and the Dutch East Indies. The British controlled the eastern half of modern Malaysia (in a variety of federations and colonies, see History of Malaysia) through a system of protectorates, in which native states had some domestic authority, checked by the British government. The eastern half of Malaysia was part of the independent Sultanate of Brunei until 1841, when it was granted independence as the Kingdom of Sarawak under the White Rajas. The kingdom would remain fully independent until 1888, when it accepted British protectorate status, which it retained until the last raja, Charles Vyner Brooke, ceded his rights to the United Kingdom.

The two halves were united for the first time with the formation of Malaysia in 1963. Modern Malaysia is a federal monarchy, consisting of 13 states (of which nine, known as the Malay states, are monarchical) and three federal territories. Of the Malay states, seven are sultanates (Johor, Kedah, Kelantan, Pahang, Perak, Selangor and Terengganu), one is a kingdom (Perlis), one an elective monarchy (Negeri Sembilan), while the remaining four states and the federal territories have non-monarchical systems of government. Neger Sembilan itself consists of a number of sub-state monarchial chiefdoms/ The head of state of the entire federation is a constitutional monarch styled Yang di-Pertuan Agong (In English, "He who is made lord"). The Yang di-Pertuan is elected to a five-year term by the Conference of Rulers, made up of the nine state monarchs and the governors of the remaining states. A system of informal rotation exists between the nine state monarchs.