In order to change your child’s last name, you will have to be the child’s parent with legal custody or be the legal guardian of the child. In order to change the child’s last name, you will have to provide notice to anyone who has legal access to the child, even if you have sole custody. Consent would not be required if: the other parent is deceased; the other parent has no access to the child; or the child is at least 18 years old. There can be a court order made which bars the parent from changing the child’s name even if the circumstances above are in place. If this is the case, you would have to apply to the court to change this order. In addition, you can only change a child’s name if they have lived in Ontario for more than a year or if the child has lived in Ontario since birth.