Possessive adjectives are used to indicate to whom the noun they determine belongs. They take the form of an adjective and are placed before the noun, like other adjectives. Their form depends on the possessed noun, not on the possessor, and they agree in gender and number with that noun.

The forms vary according to the person of the possessor and according to the gender or number of the determined noun. For a singular masculine noun, one uses mon, ton, son; for a singular feminine noun, ma, ta, sa; for a plural noun, mes, tes, ses. The plural forms of the possessor are nos, vos, leurs to express multiple possessors or a collective link.

IdéeIdea.	ExempleExample.
La première personne du singulier utilise mon, ma, mes selon le nom déterminé.The first-person singular uses mon, ma, mes according to the determined noun.	mon livremy book.
La deuxième personne du singulier utilise ton, ta, tes selon le nom déterminé.The second-person singular uses ton, ta, tes according to the determined noun.	ta chaiseyour chair.
La troisième personne du singulier utilise son, sa, ses selon le nom déterminé.The third person singular uses his, her, its according to the noun's gender and number.	ses maisonshis/her houses.
La première personne du pluriel utilise nos pour un nom pluriel déterminé.The first person plural uses nos for a definite plural noun.	nos enfantsour children.
La deuxième personne du pluriel ou le vouvoiement utilise vos pour un nom pluriel déterminé.The second person plural or the formal you uses vos for a definite plural noun.	vos idéesyour ideas.
La troisième personne du pluriel utilise leurs pour un nom pluriel déterminé.The third person plural uses leurs for a definite plural noun.	leurs amistheir friends.

The agreement is with the possessed noun, not with the possessor. A singular masculine noun takes mon, ton or son; a singular feminine noun takes ma, ta or sa; a plural noun takes mes, tes, ses, nos, vos or leurs. This agreement follows the same general principle as the Adjective Agreement.

IdéeIdea.	ExempleExample.
Le genre du nom détermine la forme du possessif.The gender of the noun determines the form of the possessive.	sa voiturehis/her car.
Le nombre du nom détermine la forme du possessif.The number of the noun determines the form of the possessive.	mes cahiersmy notebooks.
Le possesseur ne change pas la forme quand le nom change de genre ou de nombre.The possessor's form does not change when the noun changes gender or number.	son frèrehis/her brother.

The forms ma, ta and sa become mon, ton and son before a word beginning with a vowel or mute h to facilitate pronunciation. This form does not depend on the real gender of the possessor, but only on the initial sound of the determined noun. Thus we say mon amie and not ma amie.

IdéeIdea.	ExempleExample.
Ma devient mon devant voyelle ou h muet.Ma becomes mon before a vowel or silent h.	mon amiemy friend.
Ta devient ton devant voyelle ou h muet.Ta becomes ton before a vowel or silent h.	ton histoireyour story.
Sa devient son devant voyelle ou h muet.Sa becomes son before a vowel or silent h.	son écolehis/her school.

The possessive adjective always comes before the noun it modifies and before the other adjectives that follow it. We say her older sister, not older her sister. This position is the same as for other adjectives placed before the noun, such as demonstrative adjectives and certain numerical adjectives.

IdéeIdea.	ExempleExample.
Le possessif précède le nom.The possessive precedes the noun.	ma tablemy table.
Le possessif précède aussi les adjectifs qui qualifient le nom.The possessive also precedes adjectives that qualify the noun.	son petit frèrehis/her little brother.
Le possessif reste avant le groupe nominal complet.The possessive remains before the complete noun phrase.	leurs anciennes valisestheir old suitcases

Votre and vos mark the use of the formal 'you' and are used with one or more respected, unknown, or in a formal context. Ton, ta, tes are used for informal address in a familiar or close setting. The choice therefore depends on the social relationship with the interlocutor, then the agreement is with the determined noun.

IdéeIdea.	ExempleExample.
Votre s’emploie pour une personne ou un groupe vouvoié.Votre is used for a person or group addressed with the formal 'you'.	votre dossieryour file.
Vos s’emploie pour plusieurs noms ou un groupe vouvoié.Vos is used for several nouns or a plural group addressed formally.	vos questionsyour questions.
Ton s’emploie dans un contexte familier avec une seule personne.Ton is used in a familiar context with a single person.	ton amiyour friend.

The possessive adjective always accompanies a noun, whereas the possessive pronoun replaces it. We say mon livre when the noun is expressed, but mine when the noun is already known or omitted. This distinction is similar to that between adjectives and other forms attached to nouns in Formation de l'Adjectif.

IdéeIdea.	ExempleExample.
L’adjectif possessif accompagne un nom.The possessive adjective accompanies a noun.	mon livremy book.
Le pronom possessif remplace un nom.The possessive pronoun replaces a noun.	le mienmine.
Le choix dépend de la présence ou non du nom.The choice depends on whether the noun is present or not.	la siennehers.

In certain noun groups, the possessive keeps its normal position but the meaning may seem different depending on the noun. Kinship expressions follow the general rule, such as his mother-in-law or my cousins. In informal French, some possessives may be omitted or doubled, and body parts are often introduced by the definite article rather than by a possessive.

IdéeIdea.	ExempleExample.
Les noms de parenté prennent le possessif selon le nom déterminé.Kinship terms take the possessive form according to the noun.	sa belle-mèrehis/her mother-in-law.
Les parties du corps emploient souvent l’article défini.Body parts often use the definite article.	il lève la mainhe raises his hand.
Le français familier peut omettre ou redoubler le possessif.Colloquial French may omit or double the possessive.	j’ai mal à la têteI have a headache.

Possessive adjectives signal the relation of ownership by agreeing with the noun they accompany. Their form varies according to the person of the possessor, the gender and number of the noun, with mon, ton, son before a vowel to facilitate pronunciation. They are always placed before the noun, and the use of formality (the vous form), plural groups, and special cases such as kinship or body parts only modify their usage, never their function.