A court will annul a marriage only for reasons that existed at the time of the ceremony itself, and the recognized reasons for annulment are narrow: bigamy, incest, underage status, mental incapacity, physical incapacity to consummate, fraud going to the essentials of marriage, and force or duress. An annulment is a court order declaring the marriage was never legally valid, which is different from divorce, which ends a marriage that did exist.1Legal Information Institute. Annulment
Void vs. Voidable: Why the Category Matters
Every ground falls into one of two legal buckets, and the bucket decides how much work you have to do and how much time you have to do it.
A void marriage was never legally valid because it violated a fundamental prohibition. Bigamy and incest are the classic examples. Technically no court order is required to undo it, because it never existed as a legal matter, but most people obtain one anyway to create a clear public record.2Legal Information Institute. Voidable Marriage
A voidable marriage is treated as valid until someone challenges it. Fraud, duress, underage status, and mental incapacity make a marriage voidable.1Legal Information Institute. Annulment If you have grounds and never file, you stay married.
Bigamy
If either spouse was already legally married to someone else when the ceremony took place, the new marriage is void. It does not matter whether both parties acted in good faith or thought the prior marriage had ended. Until a previous marriage is formally dissolved by divorce, annulment, or death, any new marriage is a legal impossibility.1Legal Information Institute. Annulment
An innocent spouse who genuinely did not know about the prior marriage may not be left with nothing. Several states recognize the putative spouse doctrine, which protects someone who entered a bigamous marriage in good faith and can entitle them to the same property rights they would have had in a valid marriage.3Legal Information Institute. Putative Spouse Doctrine Genuine ignorance is the key requirement.
Incest
Every state voids marriages between close blood relatives. The prohibited relationships always include parent and child, grandparent and grandchild, and siblings including half-siblings. Most states also ban marriages between aunts or uncles and their nieces or nephews.2Legal Information Institute. Voidable Marriage First-cousin rules vary widely by state, with roughly half prohibiting them and the rest allowing them outright or with conditions.
Underage Marriage
A marriage involving someone below the legal age of consent is voidable. Nearly every state sets the baseline age at eighteen; Nebraska sets it at nineteen and Mississippi at twenty-one.4MOST Policy Initiative. Legal Marriage Age Marriages involving minors who lacked required parental consent or a court order can be annulled.
The right to seek annulment on this ground typically belongs to the minor spouse or their parent or guardian, and there is usually a deadline: the petition must be filed before the minor reaches the age of majority or within a short window after. If both spouses reach the legal age and keep living together voluntarily, courts treat that as ratification, and the window closes.
Mental Incapacity
Both parties must have the mental capacity to understand what marriage is and the obligations it creates. If one spouse lacked that capacity at the ceremony, the marriage is voidable. This covers severe cognitive disabilities, advanced dementia, and acute psychiatric episodes that prevented understanding of what was being agreed to.1Legal Information Institute. Annulment
Temporary impairment counts too. A spouse who was heavily intoxicated or under the influence of drugs during the ceremony may not have been able to form a binding agreement. Proving it is the hard part. Courts look at medical records, witness testimony about the person’s condition at the ceremony, and documentation of pre-existing conditions. An opinion from a treating physician or psychiatrist usually carries the most weight. If the impaired spouse regains capacity and continues living as a married couple, courts generally treat the marriage as accepted.
Physical Incapacity
An inability to consummate the marriage is a recognized ground in most states. To qualify, the physical incapacity must have existed at the time of the wedding, must be permanent and incurable, and must have been unknown to the other spouse.5Legal Information Institute. Impotence A condition that develops after the wedding is not a basis for annulment; that is divorce territory.
Courts may order medical examinations. The standard is not whether the couple can have children but whether they can engage in sexual relations at all. Psychological conditions that permanently prevent intimacy can also qualify. If the other spouse knew about the condition before the wedding, this ground is generally unavailable.
Fraud
Fraud is probably the most litigated ground, and the one where courts draw the sharpest lines. The rule is not that your spouse lied to you. Spouses lie about all kinds of things, and most of those lies are grounds for divorce, not annulment. For annulment, the fraud must go to what courts call the essentials of the marriage relationship: something so fundamental that the deceived spouse would never have agreed to marry had they known.1Legal Information Institute. Annulment
The frauds courts most consistently accept involve sex and procreation: concealing infertility, hiding a sexually transmitted disease, lying about the ability or willingness to have children, or concealing a pregnancy by someone else. Misrepresentations about wealth, personality, career success, or general character almost never qualify.
A few other categories have gained traction: concealing a serious violent criminal history, hiding a secret addiction, or marrying solely to obtain immigration status. Marrying solely to evade immigration law is also a federal crime.6Office of the Law Revision Counsel. 8 USC 1325 – Improper Entry by Alien
Timing matters. The deceived spouse must generally stop living with the other person promptly after discovering the truth. Continuing the relationship after learning about the fraud signals acceptance, and courts will refuse the annulment.
Force or Duress
Consent to marriage must be freely given. When someone agrees to marry only because of physical violence, threats of harm, kidnapping, or other coercion that overcomes their free will, the marriage is voidable.2Legal Information Institute. Voidable Marriage
The test is whether the pressure was severe enough that a reasonable person in the same situation would have felt they had no real choice. Physical force or threats of violence are the clearest cases. Psychological coercion can qualify, but the bar is high. Threats of financial ruin, public humiliation, or exposure of damaging personal information may suffice if they effectively eliminated the ability to say no. Family pressure, social expectations, and later regret do not.
The duress must have been operating at the moment of the ceremony itself, not just during the engagement. Once the threat is removed, the coerced spouse needs to act quickly. Continuing to live together once the danger has passed is treated as voluntary acceptance.
How You Can Lose the Right to Annul
A recurring theme across almost every voidable ground is ratification, and it trips up more people than any other technicality. Ratification means you knew about the problem and stayed in the marriage anyway. Once that happens, a court will treat the marriage as voluntarily accepted.
The classic scenario: you discover your spouse committed fraud, you are furious, but you keep living together for months while you figure out what to do. By the time you file, the court may rule that your continued cohabitation ratified the marriage. The same logic applies to underage marriages where both spouses have reached the legal age, duress cases where the threat has ended, and incapacity cases where the impaired spouse has regained their faculties.
Ratification does not apply to void marriages. A bigamous or incestuous marriage stays void regardless of how long the couple lives together, because cohabitation cannot cure a fundamental legal impossibility.
Most states also impose hard statutory deadlines, and they vary by ground. For underage marriages, the window often closes within 90 days of the ceremony or when the minor reaches the age of majority. For fraud, some states require the petition within one year of discovering the deception. For intoxication or duress, the deadline may be tied to when the impairment or coercion ended. Void marriages generally have no filing deadline. For voidable marriages, missing the deadline means your only option is divorce, even if the grounds were clearly present.
What an Annulment Actually Changes
The legal fiction that the marriage never existed has practical consequences, some of them harsh.
Children
Annulment does not make children illegitimate. In virtually every state, children born during a marriage that is later annulled are considered legitimate, particularly when at least one parent entered the marriage in good faith. Courts retain full authority to decide custody, visitation, and child support in annulment proceedings, applying the same best-interest-of-the-child standard they use in divorce.
Property and Support
Because the marriage technically never existed, the default rule in many states is that neither spouse has a claim to the other’s property or spousal support. Each person walks away with what they brought in and what they earned individually. That rule can produce harsh outcomes for a spouse who left a career or contributed to the household for years.
The putative spouse doctrine helps address this. In states that recognize it, an innocent spouse who believed the marriage was valid can receive a share of property acquired during the relationship, much like a divorce.3Legal Information Institute. Putative Spouse Doctrine Some states have enacted statutes giving courts discretion to divide property equitably after annulment, but coverage is far from universal. If property matters to you, check your state’s specific rules before filing.
Benefits and Insurance
Annulment can retroactively affect benefits that depended on marital status. Health insurance obtained through a spouse’s employer plan, Social Security spousal benefits, military dependent benefits, and immigration status tied to the marriage may all be disrupted. The impact depends on the specific program and whether the annulment is treated as retroactive to the ceremony or effective only going forward. Anyone relying on a spouse’s benefits should investigate the consequences for each program before filing.