Spanish has two families of possessives, and the trick is knowing which one goes where. The short (unstressed) forms sit before the noun; the long (stressed) forms come after the noun or stand alone. Both agree with the thing owned, not the owner — the single idea that unlocks the whole topic.

Let's take them one set at a time, with the agreement rules that trip up most English speakers.

Short forms: before the noun

These are the everyday possessives. They replace the article and agree in number (and, for nuestro and vuestro, in gender too).

  • my: mi / mis — mi libro, mis libros
  • your (tú): tu / tus — tu casa, tus casas
  • his / her / your (usted) / their: su / sus — su coche, sus coches
  • our: nuestro / nuestra / nuestros / nuestras — nuestra casa, nuestros amigos
  • your (vosotros): vuestro / vuestra / vuestros / vuestras — vuestro país, vuestras ideas

Notice that mi, tu and su only change for number: mi hermano · mis hermanos. Only nuestro and vuestro also flip for gender: nuestra profesora · nuestros profesores.

Long forms: after the noun and with ser

The stressed forms all agree in gender and number. Use them after the noun, after ser, or on their own.

  • mine: mío / mía / míos / mías — un amigo mío, es mío
  • yours (tú): tuyo / tuya / tuyos / tuyas — una idea tuya, es tuya
  • his / hers / theirs / yours (usted): suyo / suya / suyos / suyas — un libro suyo, es suyo
  • ours: nuestro / nuestra / nuestros / nuestras — un vecino nuestro, es nuestro
  • yours (vosotros): vuestro / vuestra / vuestros / vuestras — un problema vuestro

You'll hear them in two very common patterns: after ser · Este boli es mío — This pen is mine. And the "a friend of mine" pattern · un amigo mío — a friend of mine, una compañera tuya — a classmate of yours.

The famous su / suyo ambiguity

Because su and suyo cover his, her, their and formal your, context usually sorts it out — but when it doesn't, Spanish clarifies with de + pronoun:

  • ambiguous: su casa — his/her/their/your house
  • clarified: la casa de él — his house · la casa de ella — her house · la casa de ellos — their house · la casa de usted — your house

Note the shift: you drop su, bring back the article (la casa), and add de él / de ella.

Common mistakes

  • Agreeing with the owner: English speakers expect "his/her" to reflect the person. In Spanish, the possessive agrees with the thing owned: a woman says su libro (masculine noun), a man says su casa (feminine noun).
  • Adding an article to short forms: not el mi libro but simply mi libro.
  • Forgetting plural on mi/tu/su: it's mis amigos, never mi amigos.
  • Confusing tu and tú: tu (no accent) = your; tú (accent) = you.

Memory tip: the possessive is a chameleon that copies the noun beside it, not the person who owns it.

👉 Read also: Spanish Adjectives: agreement & gender and Spanish Articles.

Frequently asked questions

Do possessives agree with the owner or the object?

Always with the object owned. Su casa uses the feminine casa regardless of whether the owner is male or female, and mis libros is plural because there are several books, not because of who owns them.

When do I use mío instead of mi?

Use mío (and the other long forms) after the noun, after ser, or alone: un amigo mío, es mío. Use mi directly before the noun: mi amigo.

How do I avoid confusion with su?

When context isn't clear, replace su with the article plus de + pronoun: su coche becomes el coche de ella (her car) or el coche de ellos (their car).