Annulment in Ontario - when a marriage can be annulled
Last updated: June 16, 2026
An annulment is a court declaration that your marriage was never legally valid in the first place. It is not a faster or cheaper divorce — in Ontario, annulments are rare, narrow, and harder to get than a straightforward uncontested divorce. For almost every Ontario man whose marriage has ended, the route is divorce, not annulment. Annulment only fits a very small set of circumstances where the marriage was either never legally formed or never consummated.
The grounds for annulment in Ontario flow from the federal Marriage (Prohibited Degrees) Act and the common law on marriage validity. The Superior Court of Justice grants annulments under the same Family Law Rules that govern divorce, but on a different evidentiary standard (Department of Justice — Marriage and divorce).
When this does apply
An Ontario annulment is available when the marriage was never legally valid: one spouse was already married to someone else (bigamy), the spouses were too closely related under the prohibited-degrees rules, one or both spouses lacked the legal capacity to consent at the time of the ceremony (because of age, mental incapacity, fraud, or duress), or the marriage was never consummated for reasons of physical incapacity. Each ground requires proof. Lack-of-consent cases turn on what each spouse understood at the time of the ceremony; non-consummation cases require medical evidence. None of these grounds are about how the marriage went later.
When this doesn't apply
Annulment is not available because the marriage was short, unhappy, or a mistake in hindsight. It is not the route for a regretted Las Vegas wedding, a relationship that fell apart in the first year, or even infidelity discovered shortly after the ceremony. Those are reasons to file for divorce, not annul. Annulment also does not change how parenting, child support, spousal support, or property are decided — those still run under the Family Law Act and the Divorce Act the same as in any other separation, so the separation agreement work still has to happen either way.
What to do
If you think your situation might genuinely meet one of the narrow annulment grounds, get one hour of Independent Legal Advice from an Ontario family-law lawyer or paralegal before filing anything. If the legal opinion is that annulment fits, the application is similar to a divorce application but pleads the specific ground. If it does not fit — which it will not for the vast majority of cases — the simpler, cheaper route is the standard divorce application after one year of separation. Do not file an annulment application hoping to avoid the year. Courts dismiss those, and you start the divorce clock again from zero.
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Frequently asked questions
What are the grounds for annulment in Ontario?
The marriage was never legally valid - one spouse was already married (bigamy); the spouses were too closely related under the prohibited-degrees rules; one or both lacked capacity to consent at the time of the ceremony (age, mental incapacity, fraud, duress); or the marriage was never consummated for reasons of physical incapacity. Each ground requires evidence.
Is annulment harder than divorce in Ontario?
Yes. Annulment requires proving the marriage was never legally valid - which is a high evidentiary bar with narrow grounds. Divorce only requires proving marriage breakdown, almost always through one year of separation. For most Ontario men, divorce is faster, cheaper, and far easier to obtain.
How long after marriage can you get an annulment in Ontario?
There is no statutory time limit, but the longer you have been married and lived as spouses, the harder annulment becomes. Annulment grounds are about the validity of the marriage at the moment of the ceremony - not how the marriage went later. Long-cohabiting couples almost never qualify because consummation and consent are usually evident from the relationship history.
How long does an annulment take in Ontario?
A contested annulment can take longer than an uncontested divorce because the evidence required is more specific - witness testimony on capacity or fraud, medical evidence on non-consummation. For an uncontested annulment with clear grounds, the process resembles an uncontested divorce: file, serve, wait the response period, ask for the order. Without the one-year separation rule, an uncontested annulment can finish in three to four months.
Does an annulment change child support or property division in Ontario?
No. Child support, spousal support, and property division still run under the Family Law Act and the Divorce Act in the same way as any other separation. The annulment ends the legal marriage; it does not change the financial and parenting obligations that arose during the relationship.