Hong Kong's substantive law on the custody of children is primarily contained in a few Ordinances (including the Guardianship of Minors Ordinance (Cap. 13) ("GMO"), the Matrimonial Causes Ordinance (Cap. 179) ("MCO"), the Matrimonial Proceedings and Property Ordinance (Cap. 192) ("MPPO") and the Separation and Maintenance Orders Ordinance (Cap. 16) ("SMOO")).

The GMO governs court proceedings relating to the custody and upbringing of children. This Ordinance states the principle that the welfare of the child in question is to be the first and paramount consideration of the courts. The rights and authority of the mother and father of a child are equal except where the child is born out of wedlock, in which case the mother has all parental rights and authority. However, on application made by an unmarried father, the court may grant him some or all of the rights and authority that the law would allow him as a father if the child were born legitimate.

The MCO governs divorce and the MPPO contains provisions relating to ancillary and other relief in matrimonial proceedings. Section 19 of MPPO states that the court may make such order as it thinks fit for the custody and education of a child in matrimonial proceedings such as divorce. Procedural rules for custody applications are in the Matrimonial Causes Rules (Cap. 179 sub. leg.). A "sole custody" order is quite common, under which the child concerned lives with the custodial parent who has the right to make the decisions regarding the upbringing of the child. The non-custodial parent is usually granted access, which means the right to maintain contact with the child. Under section 5 of SMOO, a husband or wife may apply for the legal custody of a child of the marriage on a ground under section 3.