Inheritance Rights of an Only Child in the Philippines A comprehensive guide for lawyers, judges, estate planners, and families

Executive Summary

Under Philippine law, an only child—whether legitimate, illegitimate (now more commonly called non-marital), or adopted—is always a compulsory heir. The Civil Code’s system of legitimes gives such a child a fixed, inalienable share of every parent’s estate. The size of that share depends on three variables:

The presence or absence of a surviving spouse
The child’s civil status (legitimate, non-marital, or adopted)
Whether succession is intestate or testamentary

The table below previews the intestate shares (Article 979 et seq.). Percentages are of the net hereditary estate after paying debts, expenses, and estate tax.

Composition of compulsory heirs	Legitimate only child	Non-marital only child¹	Adopted only child²
Child alone (no spouse, no ascendants)	100 %	100 %	100 %
Child + surviving spouse	50 % child / 50 % spouse³	1/3 child / 2/3 spouse	50 % child / 50 % spouse
Child + legitimate ascendants, no spouse	50 % child / 50 % ascendants	1/3 child / 2/3 ascendants	50 % child / 50 % ascendants

¹ Civil Code Art. 895 sets the non-marital child’s legitime at ½ of a legitimate child’s; jurisprudence calling for equalization (e.g., Alcantara v. Alcantara, G.R. 227610, July 28 2021) has not yet been codified, so practitioners must still apply the statute while flagging potential constitutional challenges. ² A legally adopted child is treated “for all intents and purposes” as a legitimate child (Domestic Adoption Act, R.A. 11642, §27). ³ Civil Code Art. 892.

I. Legal Foundations

Source	Key provisions
Civil Code (Arts. 960–1105)	General rules on succession, legitimes, collation, partition, and disinheritance.
Family Code (EO 209, 1987)	Defines legitimacy, property regimes of spouses, and support obligations.
Domestic Adoption Act (R.A. 11642, 2022)	Equates adopted children with legitimate children in succession.
Estate Tax Law (NIRC Title III, as amended by TRAIN Law, R.A. 10963)	Uniform 6 % estate tax and P5 million exemption.
Supreme Court jurisprudence	Clarifies ratios between legitimate and non-marital children, void disinheritance clauses, and nationality rules.

II. When Is a Child the Sole Descendant?

An “only child” in succession means no other living legitimate or non-marital child and no descendants by representation (grandchildren stepping into their deceased parent’s place). If an older sibling pre-deceased the decedent and left offspring, those grandchildren inherit by right of representation under Art. 970, so the living child is no longer the sole descendant.

III. Intestate Succession Scenarios

A. Only legitimate child, no spouse, no ascendants

Child takes the entire estate (Art. 979).
The estate cannot be diverted to collateral relatives.

B. Only legitimate child + surviving spouse

Art. 892: each receives one-half of the hereditary estate.
If property is conjugal/ACP, first divide the conjugal partnership; only the decedent’s one-half is transmissible.

C. Legitimate child + legitimate ascendants (parents)

Child: one-half; ascendants: one-half, divided equally between paternal and maternal lines (Art. 894).
A surviving spouse here supersedes the ascendants and shares instead with the child.

D. Only non-marital child (§ II definition applies)

Shares are measured against a hypothetical legitimate child: the non-marital child gets ½, the surviving spouse or ascendants get the balance (Art. 895).
Constitutional challenges argue that the ½ rule discriminates, but it remains controlling legislation.

E. Adopted only child

Treated exactly like a legitimate child (R.A. 11642, §27).

IV. Testamentary Succession and the Legitime

A parent may dispose of the free portion by will, but may not impair the legitime:

Compulsory‐heir composition	Legitime of the only child	Free portion
Only child, no spouse	1/2	1/2
Child + spouse	1/2 (split equally)	1/2
Child + ascendants	1/2	1/2

A will giving the entire estate to a third party is reducible by action for inofficiousness (Arts. 771 & 906).

V. Special Rules Affecting an Only Child

Topic	Practical impact
Advancements/Donations (Arts. 1061 ff.)	Gifts made during the parent’s lifetime are presumed part of the legitime and must be collated, unless expressly stated otherwise.
Possibility of Disinheritance	Grounds are exhaustive (Art. 919). “Unworthiness” disinherits both legitimate and non-marital children equally.
Waiver of legitime	Waivers made inter vivos without court approval are void (Art. 1044); those made in a partition are valid.
Guardianship	If a child is a minor at the decedent’s death, the estate administrator or legal guardian (Family Code Arts. 225-236) holds the property in trust until majority.
International estates	Nationality principle (Art. 16) applies: succession rights of a Filipino only child extend to worldwide property, but foreign immovables follow lex situs for capacity to convey.
Estate tax filing	The only child, if of age, or the legal guardian, files BIR Form 1801 within one year; penalties accrue thereafter.

VI. Collation, Partition, and Settlement

Inventory and appraisal of gross estate.
Payment of debts and taxes.
Determination of legitime—calculate the net estate and allocate per Arts. 888-896.
Collation: advance gifts are imputed to the child’s share; excess must be returned in cash or property.
Partition: extrajudicial if (i) no debts or debts are fully paid and (ii) heirs* are of age (Rule 74, Rules of Court). A minor only child cannot sign an EJS; the court must approve a compromise or appoint a guardian.
Registration of titles in the Registry of Deeds and Bureau of Land Registration.

VII. Disinheritance and Restoration

A sole descendant may be disinherited only on the enumerated grounds:

Serious acts against the parent (attempt on life, false accusation of crime, etc.),
Refusal of support, or
Immoral life (legitimate child only).

If the disinheritance is proven invalid—e.g., ground not clearly specified in the will—the child keeps the legitime and the will is reduced pro tanto.

VIII. Recent Developments

Date	Case / Law	Take-away
28 Jul 2021	Alcantara v. Alcantara	SC signaled that Art. 895’s ½ ratio may violate equal-protection, hinting at parity between legitimate and non-marital children.
2022	R.A. 11642 (New Domestic Adoption Act)	Repealed R.A. 8552, reaffirmed adopted children’s status as legitimate for all succession purposes.
2023-2024	BIR Rulings on extrajudicial settlements	Clarified that a minor heir’s guardian ad litem may sign the EJS without court approval if backed by a special power of attorney approved by the RTC.

IX. Practical Checklist for the Only Child (or Counsel)

Secure PSA-issued certificates (birth, marriage, death).
Conduct title searches (Registry of Deeds, LRA, COA for government bonds).
Prepare a schedule of liabilities—mortgages, taxes, personal debts.
Compute legitime; verify any lifetime donations.
Choose settlement route
- Extrajudicial: if all requisites met.
- Judicial: if contested, estate insolvent, or minor heir lacks court-approved guardian.
File estate-tax return; pay within one year (extendable).
Transfer titles; record any leasehold or usufruct in child’s favor if usufructuary reserved by spouse.
Plan future succession—only child should execute a will or estate plan early to avoid the single-heir problem repeating in the next generation.

X. Conclusion

Being an only child in the Philippines confers the strongest possible hereditary position under the Civil Code. Whether legitimate, non-marital, or adopted, the child’s legitime can only be defeated by:

Proven disinheritance on statutory grounds, or
Prior, validly executed donations that exhaust the legitime and are accepted during the parent’s lifetime.

Otherwise, the law ensures the only child’s economic security by reserving at least one-half—and often the whole—of the estate. Estate planners should tailor wills and donations around this mandatory share, while heirs must vigilantly protect it through timely settlement, collation, and, when needed, court action to reduce inofficious dispositions.