An Esperanto possessive carries two different kinds of information. Its root identifies the possessor: mi- in mia, ili- in ilia, si- in sia. Its endings agree with the possessed noun: mia libro, miaj libroj, mian libron, miajn librojn. The possessor never directly controls -j or -n.
This differs sharply from English. English “their” is plural because the owners are plural, but Esperanto ilia can be singular when one thing is owned. Conversely, liaj is plural even though li names one owner, because several things are possessed.
First learn how each possessor selects a root on Possessive Forms in -A; this page explains the agreement endings added to that root.
The four-form pattern
Possessives are A-words, so they use the ordinary adjective agreement pattern.
| Possessed noun | Possessive form | Complete phrase |
|---|---|---|
| singular subject/complement | mia | mia libro |
| plural subject/complement | miaj | miaj libroj |
| singular direct object | mian | mian libron |
| plural direct object | miajn | miajn librojn |
The ending order is always -a-j-n: adjective ending, plural, accusative.
Mia kolego laboras hejme hodiaŭ.
My colleague is working from home today.
Miaj kolegoj laboras hejme hodiaŭ.
My colleagues are working from home today.
Mi telefonis al mia kolego post la kunveno.
I called my colleague after the meeting.
Mi renkontis miajn kolegojn post la kunveno.
I met my colleagues after the meeting.
In al mia kolego, the preposition al marks the phrase, so there is no accusative -n. In miajn kolegojn, the whole noun phrase is the direct object, so both possessive and noun carry plural -j and accusative -n.
Owner number and object number are independent
The possessor's number is already contained in the pronoun base: lia “his,” ilia “their.” The agreement ending then counts the possessed items.
| Phrase | Possessors | Possessed items |
|---|---|---|
| lia biciklo | one male person | one bicycle |
| liaj bicikloj | one male person | several bicycles |
| ilia biciklo | several owners | one bicycle |
| iliaj bicikloj | several owners | several bicycles |
Ilia domo staras ĉe la fino de la strato.
Their house stands at the end of the street.
Liaj du filinoj studas en diversaj urboj.
His two daughters study in different cities.
Ilia is singular because domo is one house, despite multiple owners. Liaj is plural because there are two daughters, despite one male possessor.
The same principle applies to via. It never reveals whether “you” means one person or several; only the possessed noun controls agreement.
Ĉu viaj biletoj estas en via sako?
Are your tickets in your bag?
Agreement across the whole noun phrase
When a noun phrase contains a possessive and descriptive adjectives, all A-words match the noun.
Ŝi surmetis sian novan ruĝan mantelon.
She put on her new red coat.
Ni lavis niajn malpurajn fenestrojn antaŭ la festo.
We washed our dirty windows before the party.
In the first sentence, sian novan ruĝan mantelon is singular accusative. In the second, niajn malpurajn fenestrojn is plural accusative. Esperanto repeats agreement because each ending makes the phrase's structure visible even when word order varies.
Numbers do not remove adjective agreement. Liaj du filinoj keeps plural liaj because the head noun is plural. In the accusative, say Mi renkontis liajn du filinojn.
Mi renkontis liajn du filinojn ĉe la stacidomo.
I met his two daughters at the station.
Sia follows the same agreement rule
The special meaning of sia affects which possessor is chosen, not how agreement works. Once sia is selected, the possessed noun controls its endings exactly as with mia or ilia.
La studento malfermis sian kajeron.
The student opened his or her own notebook.
La studentoj malfermis siajn kajerojn.
The students opened their own notebooks.
Plural subject studentoj does not by itself cause siaj. The second sentence uses siajn because kajerojn is plural and accusative. Compare a plural subject with one shared object:
La studentoj prezentis sian komunan projekton.
The students presented their shared project.
Here sian is singular accusative because projekton is one shared project. This is the cleanest proof that subject number and possessive agreement are separate systems.
Predicate possessives agree in number, not case
After esti, a standalone possessive can identify an owner: La libro estas mia. It agrees in number with the subject, but a predicate complement does not take accusative -n.
La verda ombrelo estas mia, sed la nigraj estas viaj.
The green umbrella is mine, but the black ones are yours.
Ĉu tiuj gantoj estas viaj aŭ liaj?
Are those gloves yours or his?
Viaj and liaj are plural because the understood noun gantoj is plural. Neither takes -n after estas. If the nounless possessive itself is a direct object, case returns: Mi prenis la miajn “I took mine.”
Case belongs to the phrase's role
Do not add -n because possession feels object-like. Add it only when the whole noun phrase has an accusative function. Compare:
Ŝia aŭto estas antaŭ la domo.
Her car is in front of the house.
Mi vidas ŝian aŭton antaŭ la domo.
I see her car in front of the house.
The possessor is the same woman in both sentences. Ŝia changes to ŝian only because the second noun phrase is the object of vidas.
A connected contrast
— Ĉu vi trovis niajn ŝlosilojn? — Mi trovis vian ŝlosilon, sed ne niajn.
— Did you find our keys? — I found your key, but not ours.
Niajn ŝlosilojn is plural accusative. Vian ŝlosilon is singular accusative. Final niajn keeps both endings because the omitted noun remains plural and object-like.
Common Mistakes
1. Making the possessive plural because the owners are plural
❌ Iliaj domo estas proksime.
Incorrect: there is one possessed house, so the possessive is singular.
✅ Ilia domo estas proksime.
Their house is nearby.
2. Leaving a possessive singular before a plural noun
❌ Mia amikoj venos morgaŭ.
Incorrect: mia must agree with plural amikoj.
✅ Miaj amikoj venos morgaŭ.
My friends will come tomorrow.
3. Marking only the noun as accusative
❌ Mi serĉas mia malnova pasporton.
Incorrect: accusative agreement must appear on the possessive and adjective too.
✅ Mi serĉas mian malnovan pasporton.
I am looking for my old passport.
4. Forgetting plural accusative on the possessive
❌ Ni invitis niaj novaj najbarojn.
Incorrect: both possessive and adjective require -j and -n.
✅ Ni invitis niajn novajn najbarojn.
We invited our new neighbors.
5. Letting subject number control sia
❌ La gepatroj vendis siajn aŭton.
Incorrect: one car requires singular accusative sian.
✅ La gepatroj vendis sian aŭton.
The parents sold their own car.
Key Takeaways
The pronoun base identifies the possessor; the endings agree with the possessed noun. Use -j for multiple possessed items and -n when the whole phrase is accusative: ilia domo, iliaj domoj, ilian domon, iliajn domojn. Apply the same endings to every agreeing adjective, including sia, and remember that predicate possessives after esti agree in number but do not take accusative case.
Related Topics
- Possessive Forms in -AA1 — Form Esperanto possessives by adding -a to personal pronouns and use them as determiner-like words before nouns.
- Possessives without a NounA2 — Use possessive A-words independently when the omitted noun is recoverable, retaining its number and accusative endings.
- The Possessive SiaA1 — Use sia for a third-person subject's own possession and make it agree with the possessed noun.
- Adjective Agreement in NumberA1 — Learn why Esperanto adjectives take -j when they describe plural people or things, in both noun phrases and predicates.
- Adjective Agreement in the AccusativeA1 — Learn when Esperanto adjectives copy the accusative -n, how -ajn is built, and why predicative adjectives normally remain without -n.