1) The basic legal framework

Inheritance in the Philippines is governed primarily by:

The Civil Code provisions on Succession (rules on who inherits, legitimes, intestate order, representation, partition, etc.).
The Family Code provisions on Status and Filiation (rules on legitimacy/illegitimacy, how filiation is proved, and related effects).
Special laws that can change family status, especially Adoption (which generally makes the adoptee a legitimate child of the adopter for succession purposes).

When people talk about “inheritance rights of illegitimate children to grandparents’ property,” they are usually referring to intestate succession (no will) and whether an illegitimate grandchild can inherit from a grandparent by representation or in their own right. A will changes the analysis but does not remove compulsory heirs’ legitimes.

2) Key terms that control the outcome

A. “Illegitimate child” (Philippine context)

A child is illegitimate when conceived and born outside a valid marriage, unless later legitimated or adopted (both of which can change inheritance outcomes dramatically).

B. Filiation (proof that you are the child/grandchild)

No matter how strong the moral claim is, inheritance turns on legal filiation—being legally recognized as the child of your parent (who is the child of your grandparent).

Common ways filiation is established/proved include (conceptually):

A record of birth and/or recognition
A written admission/acknowledgment by the parent
Open and continuous possession of status (treated publicly as the child)
Court action to establish filiation when disputed

Without legally provable filiation, a claimant generally cannot share in the estate.

C. Testate vs. intestate succession

Testate: the decedent left a will. The will may distribute the “free portion,” but it cannot impair the legitime of compulsory heirs.
Intestate: no will (or the will is ineffective as to part/all of the estate). Distribution follows the Civil Code order of heirs.

D. Compulsory heirs and legitime (why “grandchildren” often appear)

A grandchild typically inherits from a grandparent only when stepping into the place of a parent who would have inherited—this is representation, and it is central to grandparent-property questions.

3) The decisive doctrine: the “Iron Curtain Rule” (Civil Code Article 992)

A. What it says in effect

Article 992 is commonly called the “iron curtain rule.” In intestate succession, it bars inheritance between:

Illegitimate children and
The legitimate children and legitimate relatives of their father or mother.

It also bars the reverse direction (those legitimate relatives inheriting from the illegitimate person) in intestacy.

B. Why it matters for grandparents

In many family trees, grandparents are the legitimate relatives of the parent. So when an illegitimate grandchild tries to inherit intestate from a grandparent through a legitimate family line, Article 992 is the wall they hit.

Practical meaning: An illegitimate child generally cannot inherit intestate from the legitimate relatives of their parent, which commonly includes legitimate grandparents.

4) Can an illegitimate grandchild inherit from a grandparent intestate?

This is best answered by scenarios, because the result depends on (1) the status of the parent vis-à-vis the grandparent, and (2) whether inheritance is claimed by representation, and (3) whether Article 992 blocks the link.

Scenario 1: The parent is a legitimate child of the grandparent; the claimant is the parent’s illegitimate child

The grandparent is a legitimate relative of the parent.
The claimant (illegitimate grandchild) is illegitimate with respect to the parent’s legitimate family line.

General intestate outcome: Barred by Article 992. Even if the parent (legitimate child of the grandparent) is already dead, the illegitimate grandchild’s attempt to inherit from the grandparent by representation is typically blocked because it creates intestate succession between an illegitimate descendant and the legitimate relatives of the parent.

Consequence: The share that would have gone down that line usually goes instead to those heirs who are not blocked—commonly the grandparent’s surviving children/descendants who are legitimate in that line, plus other heirs per the intestate order.

Scenario 2: The parent is an illegitimate child of the grandparent; the claimant is that parent’s child (whether legitimate or illegitimate)

Here the line from grandparent to parent is itself an illegitimate line. Article 992 blocks illegitimate succession only against legitimate relatives, not against relatives in an illegitimate line.

General intestate outcome: In many configurations, inheritance by representation down an illegitimate line is not blocked the way Scenario 1 is—because the relationship is not one of an illegitimate person inheriting from the legitimate relatives of the parent; the line itself is illegitimate.

Important practical note: This still depends on the precise family composition (who else survived the grandparent, whether the estate is shared with legitimate children, etc.), but the crucial point is that the “iron curtain” is aimed at crossing between illegitimate and legitimate family circles in intestacy.

Scenario 3: The grandparent leaves no legitimate relatives in the relevant line (or the claimant is not trying to cross into the “legitimate relatives” circle)

If the intestate heirs are situated such that the claimant is not inheriting from the parent’s legitimate relatives, Article 992 may not be the barrier people assume it is. The analysis becomes a straight application of intestate rules and representation, subject to proof of filiation.

5) Representation: the usual route for grandchildren

A. What “representation” means

Representation is a legal mechanism where a descendant steps into the shoes of a parent (or other relative) who:

Predeceased the decedent,
Is incapacitated to inherit, or
Is disinherited (depending on the circumstances allowed by succession rules).

For grandparents’ estates, representation most commonly happens when a grandparent’s child (the claimant’s parent) would have inherited but is no longer able to.

B. The clash between representation and Article 992

Representation does not operate in a vacuum: it is still intestate succession, and Article 992 can prevent representation when the representative is illegitimate and the represented link would make them inherit from the legitimate relatives of their parent.

So, an illegitimate grandchild may say: “I am representing my deceased parent.” The law replies: “Even by representation, you are still trying to inherit intestate from the legitimate relatives of your parent,” and Article 992 may bar it (Scenario 1).

6) If there is a will: can grandparents leave property to an illegitimate grandchild?

Yes—as a rule, a grandparent may give by will to anyone who is not disqualified, including an illegitimate grandchild, but only within the limits of the free portion.

A. The will cannot impair legitimes

Even if a grandparent wants to leave everything to an illegitimate grandchild, compulsory heirs (like legitimate children, surviving spouse, and others depending on who survives) have fixed legitimes protected by law. The gift to the grandchild comes from what remains—the free portion.

B. Article 992 is an intestate rule

Article 992 is principally a bar in intestate succession. A properly executed will can therefore be a powerful way to provide for an illegitimate grandchild—again, subject to legitimes and other limitations (e.g., disinheritance rules, formalities, and capacity to inherit).

C. Donations inter vivos (during lifetime) also matter

Grandparents sometimes transfer assets during life. These transfers can later be examined in estate settlement (for example, whether they should be collated or reduced for being inofficious as against legitimes). The details depend on the type of transfer and the heirs involved.

7) Changing the child’s status can change the inheritance result

A. Legitimation (when applicable)

If the child’s parents later validly marry and the legal requirements for legitimation are met, the child may become legitimate, which can erase the Article 992 obstacle in many common grandparent-estate scenarios.

B. Adoption

Adoption generally makes the adoptee a legitimate child of the adopter(s) for succession purposes, aligning inheritance rights with legitimate status in the adoptive line. This can significantly alter who inherits from whom—but it depends on whose line is involved (adoptive grandparents vs. biological grandparents, and how the adoption statute applies to inheritance in the specific configuration).

8) Procedural reality: how these disputes actually play out

A. Estate settlement is where rights are asserted

Claims to a grandparent’s property are typically resolved through:

Judicial settlement (court-supervised), or
Extrajudicial settlement (only when permitted—generally when there are no disputes and statutory conditions are met).

If someone is excluded and later asserts rights, they may challenge the settlement/partition, subject to rules on notice, fraud, and prescription.

B. Proof and timing issues are often decisive

Common battlegrounds:

Was filiation legally established?
Was the claimant properly notified in settlement proceedings?
Was there a valid will and were formalities met?
What is the exact family tree at the moment of death? (who survived whom matters)
What properties are included in the estate? (titles, conjugal/community property issues, etc.)

C. Typical documentary pinch points

Birth certificates and recognition entries
Marriage certificates (legitimation issues)
Death certificates (order of deaths affects representation)
Titles and tax declarations (what belonged to the grandparent)
Notarial documents (wills, waivers, extrajudicial settlements)

9) Practical “rules of thumb” (and why they have exceptions)

No will + parent is legitimate child of the grandparent + claimant is illegitimate child of that parent → The illegitimate grandchild is usually barred from inheriting intestate from that grandparent because of Article 992, even via representation.
A will can provide for an illegitimate grandchild → Usually yes, but only from the free portion after respecting legitimes.
Status changes (legitimation/adoption) can reshape the whole analysis → Yes. Always map the family tree with statuses at the relevant times.
Filiation must be proven → Without legal proof of filiation, inheritance rights are generally not enforceable in practice.

10) Common misconceptions

Misconception 1: “Blood is blood, so a grandchild automatically inherits from grandparents.”

Not automatically. Philippine succession law is status-sensitive. Grandchildren often inherit only through representation, and Article 992 can block illegitimate representation into the parent’s legitimate family circle in intestacy.

Misconception 2: “Article 992 means illegitimate children cannot inherit at all.”

Wrong. Illegitimate children can inherit from their parents and from other relations depending on the family configuration. The rule is a specific barrier against intestate inheritance between illegitimate persons and the legitimate relatives of their parent.

Misconception 3: “A will can ignore legitimes.”

A will cannot validly deprive compulsory heirs of their legitimes except under strictly governed rules (e.g., valid disinheritance on statutory grounds, with required formalities and proof).

11) A structured way to analyze any real-life family tree (grandparents’ property)

List the decedent’s survivors at death (spouse, children—legitimate/illegitimate, parents, etc.).
Identify whether there is a valid will.
If intestate (fully or partly), apply the intestate order and check representation possibilities.
For any illegitimate claimant trying to inherit from a relative of a parent, check Article 992:
- Is the claimant illegitimate?
- Is the person they are inheriting from a legitimate child/relative of the claimant’s father/mother?
- If yes, intestate inheritance across that line is generally barred.
Confirm filiation evidence and whether status changed (legitimation/adoption).
Only then compute shares (legitimes/free portion if testate; shares per intestate rules if not).

12) Bottom line (Philippine context)

In intestate succession, an illegitimate grandchild is commonly prevented from inheriting from a grandparent who belongs to the parent’s legitimate family line, due to Civil Code Article 992 (the iron curtain rule)—even if the claim is framed as representation.
A grandparent can still provide for an illegitimate grandchild by will, but only within the free portion after honoring legitimes.
Outcomes can shift dramatically if the child becomes legitimate through legitimation, or becomes a legitimate child in an adoptive line through adoption, and all claims still depend on provable filiation and proper estate settlement procedure.