French possessive adjectives: mon, ma, mes and the rest

Voici ma sœur et mon frère.This is my sister and my brother.

A French possessive adjective agrees with the thing owned, not with the owner. ma sœur is feminine because sœur is feminine, whoever "I" am; mon frère is masculine because frère is masculine.

Quick shortcut: the noun sets the gender and number. mon / ton / son with a masculine noun, ma / ta / sa with a feminine noun, mes / tes / ses with any plural. A feminine singular switches to mon / ton / son when the next word begins with a vowel sound (mon amie).

The full set

• mon vélo, ma voiture, mes amis
• notre maison, nos voisins
• leur fils, leurs enfants

notre, votre and leur have a single singular form for both genders. Only the plural changes: nos, vos, leurs.

son / sa / ses is not about the owner

son, sa, ses work like all the others: they match the noun, not the person. So son livre is his book or her book, and sa voiture is his car or her car. Only the situation tells you who owns it.

• Marc mange sa pomme. (Marc eats his apple.)
• Julie mange sa pomme. (Julie eats her apple.)

Same word sa, because pomme is feminine both times.

mon / ton / son before a vowel sound

When the word right after the possessive begins with a vowel sound or a mute h, a feminine noun phrase takes mon / ton / son instead of ma / ta / sa, so the two words link smoothly:

• ✅ mon amie (not ❌ ma amie)
• ✅ ton école (not ❌ ta école)
• ✅ son histoire (not ❌ sa histoire)

It is the following word that matters, not the noun itself. If an adjective starting with a consonant comes between, ma / ta / sa comes back: ✅ ma chère amie, but ✅ mon ancienne amie (adjective starts with a vowel).

The noun stays feminine either way — mon amie takes feminine agreement elsewhere (mon amie est gentille). Only the possessive takes the masculine form.

Repeat the possessive when the forms differ

French repeats the possessive before each noun whenever the forms are not the same. mon père is masculine and ma mère is feminine, so both words are needed:

• ✅ mon père et ma mère (my father and my mother)
• ❌ mon père et mère

When one form fits every noun in the group, it can cover them all: mes frères et sœurs, ses amis et collègues. Repeating it (mes frères et mes sœurs) is always safe too.

No 's — use de for a named owner

French has no 's ending. To say whose something is when you name the person, use de:

• le livre de Marie (Marie's book)
• la voiture de mon frère (my brother's car)

With a pronoun owner, the possessive adjective does the job: mon chien, leur maison.

Common mistakes

• ❌ ma amie → ✅ mon amie (feminine, but the next word starts with a vowel → mon)
• ❌ sa école → ✅ son école (same rule for ta / sa)
• ❌ son only for a male owner → son / sa match the noun; sa maison is his or her house
• ❌ leurs maison (one house) → ✅ leur maison; several → ✅ leurs maisons
• ❌ mon père et mère → ✅ mon père et ma mère
• ❌ notre amis → ✅ nos amis (plural noun → nos)

Quick check

Choose the right possessive.

1. je + sœur → ____ sœur
2. tu + ami → ____ ami
3. elle + école → ____ école
4. nous + parents → ____ parents
5. ils + maison → ____ maison

Key takeaways

• A possessive adjective takes its gender and number from the noun, not from the owner.
• Forms: mon / ma / mes, ton / ta / tes, son / sa / ses, notre / nos, votre / vos, leur / leurs.
• son / sa / ses means his, her or its — the situation, not the word, tells you which.
• mon / ton / son when the next word starts with a vowel sound or mute h (mon amie, son école) — but ma chère amie if a consonant-initial word comes between.
• Repeat the possessive when the forms differ: mon père et ma mère (but mes frères et sœurs is fine).
• There is no 's; a named owner takes de: le livre de Marie.