Short answer. A minor, a non-resident of the Philippines, or someone the court finds unfit due to drunkenness, improvidence, want of understanding or integrity, or a conviction for an offense involving moral turpitude, is not competent to serve as executor or administrator.
What the law says
No person is competent to serve as executor or administrator who: (a) Is a minor; (b) Is not a resident of the Philippines; and (c) Is in the opinion of the court unfit to execute the duties of the trust by reason of drunkenness, improvidence, or want of understanding or integrity, or by reason of conviction of an offense involving moral turpitude.
Rule 78, Section 1 — Who are incompetent to serve as executors or administrators. Read the full provision →
Being a minor is an absolute disqualification
The first ground is straightforward: a person is a minor. No matter how capable or trusted a minor might otherwise seem, age alone disqualifies them from serving as executor or administrator — this is not a discretionary finding the court weighs, but a fixed bar that applies automatically.
There is no exception for an unusually mature or otherwise responsible minor; the rule draws its line strictly at legal age.
Non-residents of the Philippines are disqualified
The second ground disqualifies anyone who is not a resident of the Philippines. Managing an estate under the supervision of a Philippine court is meant to be handled by someone actually present and accessible within the jurisdiction, not someone administering the estate from abroad.
This residency requirement makes practical sense given how closely and directly a court supervises the administrator's ongoing conduct throughout the whole estate proceeding.
A discretionary finding of unfitness is the third, broader ground
The third ground gives the court real discretion: a person in the opinion of the court unfit to execute the duties of the trust by reason of drunkenness, improvidence, or want of understanding or integrity, or by reason of conviction of an offense involving moral turpitude is disqualified. Unlike the first two grounds, this one requires the court to actually form a judgment about the specific person's fitness, based on these particular statutory grounds and whatever relevant evidence is actually presented before it at the corresponding scheduled hearing itself.
Why these disqualifications matter to anyone nominating a candidate
A family or creditor proposing a particular person to serve as executor or administrator should check that candidate against these three grounds before formally nominating them, since a disqualified nominee's appointment can be challenged and set aside later on. Confirming residency, age, and the absence of any disqualifying conduct or conviction avoids wasted time on a candidate the court cannot ultimately approve or confirm in office.