Мой, твой, его, её, наш, ваш, их — showing who owns what.
Possessive pronouns answer the question "whose?" (чей?). Most of them — unlike English "my, your, our" — change their ending to agree with the gender and number of the noun they describe, not the owner. This is a key difference from English that trips learners up early.
| Owner | Masculine | Feminine | Neuter | Plural |
|---|---|---|---|---|
| my | мой | моя | моё | мои |
| your (informal) | твой | твоя | твоё | твои |
| our | наш | наша | наше | наши |
| your (formal/plural) | ваш | ваша | ваше | ваши |
Unlike мой/твой/наш/ваш, the third-person possessives его (his/its), её (her/its), and их (their) never change form, regardless of the noun they describe. Его дом (his house), его книга (his book), его окно (his window) — the possessive stays fixed as его in every case. This makes them easier to use correctly once you know the rule, since there's nothing to agree.
Мой брат (my brother, masculine) but моя сестра (my sister, feminine) and моё имя (my name, neuter). The possessive pronoun always mirrors the gender of the object owned, never the gender of the speaker — a woman still says мой дом, not моя дом, because дом (house) is grammatically masculine.
Russian has a special reflexive possessive, свой, meaning "one's own," which refers back to the subject of the sentence regardless of person. Compare: Он взял его книгу (He took his [someone else's] book) versus Он взял свою книгу (He took his own book). This distinction doesn't exist in English and is one of the more important nuances to internalise at the intermediate level — свой also declines by gender and number exactly like мой/твой.