Possessive adjectives

In Spanish, the possessive adjective always goes before the noun, just like in English. It agrees in number (singular/plural) with the noun that follows — not with the owner!

• mi/mis = my
• tu/tus = your (informal)
• su/sus = his, her, your (formal), their

These three forms do not change for gender: mi padre (my father) and mi madre (my mother) both use mi.

Nuestro (our) and vuestro (your, plural informal) are the only possessive adjectives that do change for gender and number, just like a regular adjective ending in -o.

Vuestro is used mainly in Spain for the informal plural 'you'. In Latin America, su/sus (from ustedes) is used instead.

Su and sus can mean four things: his, her, your (formal), or their. Context usually makes clear who is meant. When it's unclear, you can clarify with de él (of him), de ella (of her), de usted (of you) or de ellos/ellas (of them):

Es su casa → Es la casa de ella (it's her house).

Besides mi, tu, su… there is a second set: the stressed possessives mío, tuyo, suyo, nuestro, vuestro, suyo (each with 4 forms: -o/-a/-os/-as). These go after the noun, or stand alone (without an article) after the verb ser, meaning 'of mine, of yours…'.

• un amigo mío = a friend of mine
• Este libro es mío = this book is mine (not mi)

With an article in front, they become a pronoun replacing the noun: el mío (mine, the one belonging to me).