leur vs leurs

Summary

leur has two grammatical lives: as an indirect-object pronoun before a verb it means "(to) them" and is invariable (never *leurs), while as a possessive adjective before a noun it means "their" and takes -s when the noun is plural (leur maison, leurs enfants).

Explanation

The single form leur does two unrelated jobs, and only one of them can ever take an -s. Sorting them out is a matter of asking what leur is sitting next to: a verb or a noun. That one question settles both the meaning and whether an -s is allowed.

Job one: leur as an indirect-object pronoun. Placed before the verb, it replaces "to/for them" (à eux / à elles): Je leur parle (I talk to them), Il leur a donné un cadeau (he gave them a gift), Nous allons leur écrire (we're going to write to them). In this role leur is invariable — it stays leur no matter how many people are meant, because a pronoun does not agree in number the way a possessive does. Writing *je leurs parle is always an error.

Job two: leur / leurs as a possessive adjective. Placed before a noun, it means "their" and agrees with the thing possessed, not with the owners: leur maison (their house — one house), leur voiture (their car), but leurs enfants (their children — several), leurs idées (their ideas). Since the owners are always plural ("they"), only the number of the possessed noun decides between leur and leurs.

There is also a possessive pronoun built on the same root: le leur, la leur, les leurs ("theirs"). It replaces "their + noun" and agrees with that noun's gender and number: Ma voiture est rouge, la leur est bleue (mine is red, theirs is blue); Nos enfants et les leurs (our children and theirs). Here the article (le/la/les) already signals the number, and leurs takes -s in the plural.

The traps for English speakers are two, and they pull in opposite directions. First, adding -s to the pronoun: because "them" feels plural, learners write *je leurs téléphone; but the verb-side leur never varies. Second, failing to agree the possessive: writing *leur enfants for several children; the noun-side leur must become leurs before a plural noun. English "their" is invariable, so English speakers under-mark the plural on the possessive and over-mark it on the pronoun.

Rule of thumb: is leur touching a verb? Then it is the pronoun "(to) them" — always leur, no -s. Is leur touching a noun? Then it is the possessive "their" — add -s only if that noun is plural (leur / leurs).

Examples

Je leur téléphone ce soir. — I'm calling them tonight. (Indirect-object pronoun before the verb -> invariable leur, no -s.)

Leur maison est au bout de la rue. — Their house is at the end of the street. (Possessive before a singular noun -> leur.)

Leurs enfants vont à la même école. — Their children go to the same school. (Possessive before a plural noun -> leurs; the owners' number is irrelevant.)

Nous allons leur offrir des fleurs. — We're going to give them flowers. (Pronoun before the infinitive -> leur, still invariable.)

Ma chambre est petite ; la leur est immense. — My room is small; theirs is huge. (Possessive pronoun la leur agreeing with chambre (feminine singular).)

Je leur ai rendu leurs livres. — I gave them back their books. (Both in one sentence: pronoun leur (invariable) + possessive leurs (plural noun).)

Common mistakes

Related rules

• Indirect-object pronouns (lui / leur)
• Possessive adjectives (mon / ma / mes)
• Possessive pronouns (le mien, le tien)