How to Change a Child's Last Name After Divorce in Ontario

Changing your own name after divorce is straightforward. Changing your child's name is a different process entirely — one that requires either both parents' consent or a court order. Getting this wrong can create a legal dispute that costs far more than the name change itself.

The Consent Requirement

Under Ontario's Change of Name Act, changing a child's legal surname requires the written consent of every person who has custody or joint custody of the child. In most post-divorce situations, this means both parents must agree.

If both parents consent, the process is the same as any legal name change:

• File Form 11155E (Application to Change a Child's Name) with the Office of the Registrar General in Thunder Bay
• Include signed consent from both parents
• Pay the CA$137 filing fee
• Wait for processing (typically 6–8 weeks)

For children aged 12 and older, the child's own written consent is also required.

When the Other Parent Won't Consent

If one parent refuses to consent, the parent requesting the change must apply to the Ontario Superior Court of Justice for a court order. The court will consider:

• The best interests of the child (the overriding consideration)
• The child's views (for older children)
• The reasons for the proposed change
• The impact on the child's identity and relationship with both parents
• The degree of connection to the current surname

Courts are generally reluctant to change a child's surname without both parents' consent, especially when the other parent maintains an active relationship with the child. The applicant bears the burden of proving the change serves the child's best interests.

Practical vs. Legal Name Changes

Some parents try to use a different surname for their child at school or medical offices without going through the legal process. This creates problems:

• Schools will use the name on official records (birth certificate or legal name change certificate) for transcripts, report cards, and standardized testing
• Medical providers use the name linked to the child's OHIP card
• Passport applications require the child's legal name

Using an informal name does not change any official records and can create confusion when documents do not match.

Updating School and Medical Records After Divorce

Even without a name change, you may need to update your child's records after divorce:

School Records

• Update emergency contact information — remove your ex-spouse if they should not be contacted, or update their new address and phone number
• Ensure the school has a copy of the custody order or parenting plan so they know who can pick the child up
• Update authorized pickup lists
• Notify the school of any access restrictions from the court order

Medical Records (OHIP and Healthcare Providers)

• If the child's health card lists the wrong parent as the primary contact, update it at ServiceOntario
• Notify the child's doctor, dentist, and any specialists of the new family structure
• Ensure both parents have access to the child's medical information (unless the court order restricts this)

The Bottom Line

Changing a child's surname is legally more complex than changing your own — it requires either joint consent or a court order, and courts prioritize the child's best interests over the parent's preferences.

For the full range of post-divorce administrative steps — including adult name changes, ID updates, financial account closures, and estate planning — the Ontario After-Divorce Checklist covers everything in order.

See more Ontario guides →