Trinidadian and Tobagonian nationality law is regulated by the Trinidad and Tobago Constitution Order of 1962, as amended; the 1976 Citizenship Act, and its revisions; and various British Nationality laws. These laws determine who is, or is eligible to be, a national of Trinidad and Tobago. Trinidadian and Tobagonian nationality is typically obtained either on the principle of jus soli, i.e. by birth in Trinidad and Tobago or under the rules of jus sanguinis, i.e. by birth abroad to parents with Trinidadian and Tobagonian nationality. It can be granted to persons with an affiliation to the country, or to a permanent resident who has lived in the country for a given period of time through naturalisation. There is not currently a program in Trinidad and Tobago for persons to acquire nationality through investment in the country. Nationality establishes one's international identity as a member of a sovereign nation. Though it is not synonymous with citizenship, for rights granted under domestic law for domestic purposes, the United Kingdom, and thus the commonwealth, have traditionally used the words interchangeably.

Acquiring Trinidadian and Tobagonian nationality Trinidadian and Tobagonian is acquired through birth, registration, or naturalisation.

By birth/descent Persons who are born within the territory, except if the foreign parents have diplomatic immunity; or Persons who are born abroad to at least one parent who was born in Trinidad and Tobago.

By registration Nationality by registration includes those who have familial or historic relationship affiliations with Trinidad and Tobago. Persons who acquire nationality by registration include:

Commonwealth nationals, nationals of the Republic of Ireland, or British Protected Persons, after five years of residence in the territory; Foreign spouses of Trinidadian and Tobagonian nationals who have renounced previous nationality; Minors under age of eighteen who are legally adopted by a national of Trinidad and Tobago; or Any minor at the discretion of the Minister responsible for immigration.

By naturalisation Ordinary naturalisation may be granted to adult persons of full capacity who satisfy the Minister responsible for citizenship that they are of good character, have adequate knowledge of the English language, and intend to reside in Trinidad and Tobago. Applicants must have resided in the country for a continuous period of 12 months immediately prior to application and must also have resided in Trinidad and Tobago, or performed government service, or a combination of both, for at least five years within the seven years preceding that 12-month period. Upon approval, applicants must take the Oath of Allegiance. In certain cases, the Minister may require renunciation of previous citizenship.

Loss of nationality Nationals may voluntarily renounce their affiliation with Trinidad and Tobago, if the declarant is a legal adult and of full capacity. Renunciation may not be accepted if the country is in a war with the proposed new source of nationality. Denaturalisation may occur if a person obtained nationality through fraud, false representation or concealment. In the case of citizens by naturalisation or registration, citizenship can be affected if they subsequently and voluntarily acquire another citizenship.

Dual nationality Dual nationality in Trinidad and Tobago has been recognized since 29 July 1988, for nationals by birth or descent. It is also generally permitted for citizens through naturalisation or registration, without a requirement to renounce a previous nationality at the time of acquisition. However, naturalised or registered citizens may be restricted from certain high public offices, and constitutional provisions may affect citizenship status or eligibility in specific circumstances involving the subsequent acquisition of another nationality.

History Spanish, Dutch, and French colonial period (1498–1802) On Christopher Columbus' fourth voyage in 1498, he landed on Trinidad and sighted Tobago, which was known by various Spanish names including Bella Forma, Isla de Asunción, Isla de Concepción and Isla de Magdalena. Until 1530, when a governor, Antonio Sedeño, was appointed, Trinidad was neglected by the crown. That year, Sedeño landed on Trinidad and built a small fort on the Paria Peninsula of Venezuela, but left it to secure reinforcements. In his absence, the fort was occupied in 1531 by Diego de Ordaz who explored the area, but then abandoned it and moved on to Cubagua. In 1580, Antonio de Berrío y Oruña inherited from his wife's uncle, Gonzalo Jiménez de Quesada, a royal decree allowing exploration of the Llanos, bounded on the north by the Pauto River and by the Caquetá River to the south. The couple left Spain and arrived in Bogotá that year. Between 1584 and 1590, de Berrío explored the land in the Orinoco Delta. In 1591, de Berrío was appointed governor of Trinidad and the Orinoco, and soon after his arrival established the town of San Thomé de la Guayana, currently known as Guayana Vieja. De Berrío sent out an expedition of 40 men, led by Domingo de Vera e Ibargoyen, to establish the first settlement on Trinidad. On 15 May 1592 the group founded San José de Oruña. Though Spain attempted to establish settlements on Tobago in 1591 and 1614, none were successful.

Nationality in the Spanish Empire was based in custom, rather than law. People born in Spain or Spanish America were considered to be members of the community and those born outside of those territories, whether of Spanish descent or not, were considered to be foreigners. Typically, naturalization was interpreted as personal, something granted to an individual, who met specified criteria. The first provisions for foreigners to be allowed to operate in Spanish territories were known as Carta de naturaleza, established by royal decree in 1567. Naturalization gave an alien the same rights as a native, but did not change their legal status as a foreigner, and was only operable within the specific territory in which one was naturalized. In colonial Spanish America, as had been established by the Siete Partidas (Seven-Part Code) enacted by Alfonso X of Castile in the 13th century, families were organized with a male head of household, who controlled the power, required obedience, and provided support and protection. Married women were legally required to submit to their husband's authority to maintain family unity.

The defeat of the Spanish Armada, in 1588, led to Spanish decline as an international powerhouse, which was replaced by Dutch, English, and French merchants and explorers. By 1611, despite the Spanish monopoly on trade with their colonies, Dutch, English, and French ships were exchanging goods in Trinidad, and widespread participation in illegal trading with foreign powers thwarted government attempts to stop it. In 1628, the Dutch successfully colonized Tobago, which they renamed New Walcheren. They were repelled by the Kalinago people, rebuilt their colony, but were driven off by the Spanish in 1636, leading them to settle on the northern coast of Trinidad. In 1628, Philip Herbert, 4th Earl of Pembroke was granted Trinidad and Tobago by Charles I of England, but failing in his colonization attempt at Tobago in 1638, he sold his patent to Robert Rich, 2nd Earl of Warwick. After three failed attempts to settle there in 1639, 1642, and 1647, Rich sold his patent.

Jacob Kettler, Duke of Courland, in present-day Latvia, claimed to have been the silent purchaser. Kettler had first attempted to establish a colony on Tobago in 1639, but it failed after repeated attacks by the indigenous Kalina people and Kalinago from neighboring islands. Courlanders attempted colonizations in Tobago again in 1642, 1645, 1649, and 1653. The last attempt finally resulted in success, when Jacobusstadt, near present-day Plymouth, was founded in 1654. Shortly thereafter, Adrian and Cornelius Lampsins from Middelburg and Vlissingen in the southwestern Netherlands, established a colony in Tobago, agreeing to recognize the Duke of Courland and pay him an annual tribute. The following year, the Dutch Parliament granted the Lampsins patents for Tobago and the rights of development and exploration. As both the Dutch and Courlander settlements were primarily founded as commercial enterprises, nationality did not play a large role in the governance. Roman-Dutch common law, per the Order of Government () of 1629, was the foundation of the legal code in the colonies, and there was no national civil law defining the rights or obligations of inhabitants. The Duke of Courland granted three years of duty-free trade, after which customary fees were required. Slaves were to be purchased from him and he granted foreigners the rights to reside in the colony if they pledged allegiance to him.

During the civil war in Courland, Kettler was imprisoned in Sweden, and the Dutch took over Tobago in 1660, transporting the remaining Corlanders back to Europe and promising to return the settlement to the duke if he regained his freedom. French settlement had been increasing on the island and they had settled primarily in the Courlander territory and in 1662 Louis XIV of France granted his patronage and the Barony of Tobago to Cornelius Lampsins. In 1664, Charles II of England entered into a secret agreement with Kettler to retake control of Tobago from the Dutch, but the Dutch learned of the plan. In 1665, the Second Anglo-Dutch War broke out and aided by the French, the Dutch were victorious. Under the terms of the 1667 Treaty of Breda all colonies returned to their previous owners, restoring Tobago to the Dutch, without mention of the Courlander or French claims to the island. In 1668, Kettler initiated a legal action in The Hague to reclaim his colony, but eventually abandoned the claim. In 1672, the British attacked the Dutch settlements on Tobago, as a first Caribbean assault in the Third Anglo-Dutch War. At the close of the war in 1674, terms of the Second Peace of Westminster returned Tobago to the Dutch. The Dutch would remain in control of Tobago until 1678, when it passed to France at the conclusion of the Franco-Dutch War.

The Ancien Régime of France developed a system of feudal allegiance in which subjects were bound together by a scheme of protection and service tied to land ownership. Possession of land was typically tied to military and court service and omitted women because they could not perform those obligations. Thus, French nationality derived from place of birth in French territory, until the nineteenth century, but under feudal law married women were subjugated to the authority of their husbands under coverture. As a part of the French Empire, the colonies in the French Antilles were subject to the provisions of the Code Noir decreed by Louis XIV in 1685. The Code was designed to control the social relations between blacks and whites in the Caribbean. It provided naturalization for freed persons and contained provisions for manumission and emancipation of slaves. Though it did not prohibit the marriage of blacks and whites, the Code carried substantial fines and penalties for owners who produced illegitimate children with slaves. Marriage to a slave woman in a church, automatically manumitted her and any children of the marriage. Children followed the status of the mother, regardless of the father's status, thus if she was a slave her children were slaves and if she was free her children were free.