A Primer on International Family Law

[This post is one in a series of primers on different topics in transnational litigation. To access other primers, please click on the “Topics” drop-down menu above.]

International family law focuses on two discrete areas of international practice: (1) private international law, and (2) comparative family law. This area of practice is traditionally broken down into several topics, each with its own legal principles. The key topics include marriage, divorce, custody and movement of children, child support, spousal support, and financial rights and remedies. In addition, there are some areas of developing law, such as parentage and family formation (such as through adoption or surrogacy) and unmarried partnership rights. International family law also touches upon other areas of practice, such as tax, bankruptcy, immigration, and immunity.


People elect to legally marry for a variety of reasons. The decision to marry implicates a wide range of legal issues, including the right to inherit, the right to receive health insurance, and the right to access tax benefits.

Individuals may, for example, choose to marry someone from another country or to contract their marriage in another country by having a “destination wedding.” The laws vary from country to country (and in the United States, from state to state) on what is required to validly contract a marriage in a particular jurisdiction. These requirements range from filing formal legal paperwork in advance of the ceremony, to using a specific credentialed individual to preside over the ceremony, to saying precise words in front of a witness. In some jurisdictions, marriages can be contracted less formally, such as by customary practice or by holding oneself out as married for a period of time, such as in a common-law marriage.

Assuming a couple legally contracts their marriage in one jurisdiction, they may run into complications if they then move to another jurisdiction. In 1978, the Hague Conference on Private International Law (HCCH) promulgated the Convention on Celebration and Recognition of the Validity of Marriages to provide for more streamlined recognition of foreign marriages. To date, however, only three countries have ratified this Convention (the United States is not one of them). In the absence of a treaty, each country sets its own rules for when it will recognize a marriage that was contracted in another jurisdiction. In the United States, the general rule is lex loci contractus; in other words, a U.S. court generally will recognize as legal and valid a marriage contracted in another country so long as the spouses complied with the relevant rules in that jurisdiction. This general rule is, however, subject to a public policy exception. U.S. courts may refuse, for example, to recognize polygamous marriages contracted in another country even if the marriage was legal under the laws of that country.

Divorce and Dissolution of Marriage

Unfortunately, not all marriages are happy. The threshold for dissolving a legal marriage varies by jurisdiction. Some jurisdictions have adopted what is called “no fault” divorce, which allows a spouse to petition a tribunal for a divorce for mere incompatibility or irreconcilable differences. Other jurisdictions require that the spouse seeking a divorce prove some fault on the part of the other party to the marriage, which may make extricating oneself from a marriage difficult or impossible.

Most jurisdictions require some type of connection (beyond consent) to obtain a divorce in a particular country (or U.S. state, since each U.S. state has its own laws and requirements). In the United States, for example, Williams v. North Carolina (1945) requires that at least one of the spouses be domiciled in a state for that state to have the requisite connection to dissolve the marriage. Consequently, after Williams, many U.S. states have held that a divorce secured in a foreign country, where neither spouse is domiciled, is not entitled to recognition. This issue of whether a divorce was properly obtained is hugely consequential. It will affect whether a subsequent marriage can be legally contracted. It will also affect whether a person is legally obligated to pay taxes, entitled to inherit property, or able to immigrate to the United States. To further complicate matters, other countries may grant divorces when one spouse is merely a national of that country, irrespective of whether he or she is domiciled there.

Although some countries that permit consensual divorces allow them to be filed administratively, most divorces in most countries have the status of a final court judgment. The question then becomes whether a foreign jurisdiction’s divorce judgment should be recognized. Spouses domiciled in different countries sometimes race to their respective courthouse to file for divorce. They then take steps to legally serve the other in an attempt to thwart the other’s legal proceeding. The strategy is clear—forum-shopping for a jurisdiction that may ultimately decide not just the divorce but the financial incidents of the divorce in a way more favorable to the filing spouse.

In 1970, the HCCH promulgated a Convention on the Recognition of Divorces and Legal Separations. While it is more widely accepted than the Marriage Convention discussed above, with twenty Contracting States, it still has yet to receive as many adoptions as the HCCH’s other treaties relating to family law. The United States has not signed this Convention either.

Custody and Movement of Children

When a separating couple has children, the stakes are higher and the legal issues more complicated. There are a significant number of practical considerations, ranging from school, to friends, to medical treatment, to the impact of long-haul flights on children, when parents are trying to create an international parenting plan that requires their children to transit between two or more countries. Inevitably, there will be issues of securing passports, visas, and travel permissions, none of which is simple.

Things become even more complicated when feuding parents seek court intervention in their parenting or custody cases, whether to obtain a court’s blessing of their voluntary parenting agreement or to have a court resolve their dispute. Custody laws vary dramatically from country to country (and, at times, from state to state), so it is critical for a parent to understand the impact of moving with children, particularly when moving may bring them within the ambit of the laws of another country. For example, some countries have presumptions that parents must share joint custody, including joint time with their children, which is often cumbersome for families with connections to more than one jurisdiction. Other countries may provide for custody by only one parent (perhaps based on religion or gender), with relatively few rights for the other parent. In many cases, the result may depend on which country’s courts are called upon to resolve the custody issue, and the law applied by the courts seized with jurisdiction.

Most countries require some connection to the child before deciding the custody issue. In the United States, for example, that connection is delineated in a uniform law, enacted in some form by every U.S. state (with Massachusetts enacting a predecessor version of the law). This uniform law prioritizes jurisdiction in a child’s home state (where a child has resided for the six months immediately before filing the lawsuit with a parent or a person acting as a parent, not counting any temporary absences from that home state). The uniform law specifically says that another country can be a child’s home state, meaning that if a parent files a lawsuit in a U.S. state, and that U.S. state’s courts determine another country is the home state, then the parent must seek recourse in that other country (even though the other country may decline jurisdiction).

Other countries define the connections between child and jurisdiction differently. Some countries assume jurisdiction over a child based on the child’s physical presence, the nationality of the child or the parent, or other pending litigation in the courts of that country. Whether U.S. courts will recognize a foreign custody order will hinge on whether the foreign court asserted jurisdiction in a way that substantially conforms with U.S. jurisdictional principles. If it does, and there was due process, U.S. courts will almost always register and enforce a foreign child-custody order.

In 1996, the HCCH promulgated the Convention on Jurisdiction, Applicable Law, Recognition, Enforcement, and Cooperation in Respect of Parental Responsibility and Measures for the Protection of Children.  This treaty, among other things, dictates jurisdiction for child custody (and other children’s) cases. The United States signed the Convention in 2010 but has yet to ratify it.

It is not uncommon for parents to seek to move their children from one country to another. When a parent does this with proper legal permission (from the other parent or a court with jurisdiction), it is called “relocation.”  There is no global legal standard for when a court permits a parent to relocate a child, but the HCCH convened a meeting in 2010 to discuss this topic, and it approved a set of principles called the Washington Declaration, which has yet to take firm hold in practice. When a parent moves their child without proper legal permission, or travels with their child and then keeps them outside of the child’s home jurisdiction, this is considered a parental child abduction.

In 1980, the HCCH promulgated the Convention on the Civil Aspects of International Child Abduction. One hundred and three countries have become a party to this Convention, including the United States. It aims to promptly return children who are abducted by a parent from a Contracting State. It provides for a network of Central Authorities (government offices) in Contracting States to help streamline the process of returning an abducted child.  Separate and apart from this civil remedy, many countries criminalize the act of parental abduction, including in the United States, which has made the removing (or attempting to remove) a child from the United States to another country, or retaining a child outside of the United States, a federal crime.

Child Support

It benefits children, families, and taxpayers to have a robust system of ensuring that children, regardless of their location, are financially supported. Each country determines who has a legal obligation to provide support to a child, as well as how much support and for how long. Child support is a right of the child. If the obligation to support a child endures into the child’s legal majority, that child may have standing to seek unpaid support. In 2007, the HCCH promulgated the Convention on the International Recovery of Child Support and Other Forms of Family Maintenance that provides for more streamlined recognition of child support obligations from country to country and the enforcement of these obligations against a parent abroad. The United States ratified this Convention in 2016.

Many countries will assert jurisdiction to make an initial child support order based on residence of the child and, usually, the parent seeking support. The United States, however, adheres to a different jurisdictional basis to establish an initial child support order—the connections to a paying parent. This tension may, at times, lead to conflicting child support orders. Tension between countries also arises when a parent seeks to modify or terminate a support obligation.

In the United States, each U.S. state tends to have a specific age at which child support ends (many at age 18, although some at age 21 or older).  Other countries may set more fluid end dates for support, which often lasts until the child is “self-supporting” (routinely meaning that the child can still collect support through university and potentially through graduate studies). Furthermore, because the United States applies its own law in setting an amount of support, a child who lives in another country may receive a windfall (if the cost of living is much lower than the United States) or a shortfall (if the cost of living is much higher).

Spousal Support/Alimony/Maintenance

Spousal support is a complicated area of law, even within the United States, because many states do not concretely define the amount or duration of a spousal support obligation or the circumstances under which it may be obtained in the first place or modified later. For purposes of multi-jurisdictional families, given the uncertainty of spousal support and the concerns that it could endure for long periods of time in some jurisdictions (or be non-existent in others), there is routinely a need to forum-shop and potentially to race to the courthouse to be the first to file for divorce.

Financial Rights of Spouses

Families may find themselves stuck in complicated messes when they divorce in one jurisdiction but own property in another. While courts typically adhere to in rem jurisdictional principles, when a court hearing the divorce has personal jurisdiction over the non-resident spouse, it may order transfers of money to compensate for assets the court cannot reach.

Finances tend to be complicated for multi-jurisdictional families. There are obvious complications in assessing the value of assets in foreign countries. It is also important to understand precisely how a spouse takes legal title (particularly over inherited property), whether a court can transfer assets between spouses (for instance, a U.S. retirement account must, in most circumstances, be transferred by a U.S. court order rather than a foreign court order), how to define the marital assets that can be divided at the time of divorce, and what to do with any legal designations or agreements that were signed before or after the date of the marriage.

In some countries, it is common to select at the time of marriage a regime by which assets are divided at the time of divorce. But these designations will not always be recognized by a court in the country to which the spouses move after they marry. Some couples enter legal arrangements, drafted by religious entities, civil law notaries, or legal counsel. These “prenuptial agreements” may not meet all the legal requirements of the jurisdiction where the parties seek to divorce, which may be different than the one they contemplated at the time of the agreement. These situations will routinely require the application of foreign law by the court hearing the divorce to decide whether to give legal effect to the agreement, or even to understand and adhere to the terms in the agreement.


Marriage, divorce, custody, support, and division of assets raise complex legal issues in transnational cases. Moreover, the rules that govern these cases—whether established by international conventions or domestic law—are often different from those that apply in kinds of transnational litigation. Needless to say, parties involved in such cases need experienced counsel, and this primer (which does not constitute legal advice) is no substitute for such counsel.