Possessive pronouns replace the noun and indicate ownership, relation, or possession. They respond to ideas such as who owns something or to whom it belongs, without repeating the object's name. They relate to the Pronouns and to the Personal Pronouns because their reference usually comes from a grammatical person.

The most common stressed forms are mío, mía, míos and mías, and they completely replace the noun. With these forms, agreement is with the possessed: gender and number depend on the thing or person that belongs, not on the possessor. In general Spanish, these forms usually appear with a definite article, as also happens with the Possessive Adjectives but with a different function.

IdeaIdea	ExampleExample
La forma cambia según el género.The form changes according to gender.	Es mía.It's mine.
La forma cambia según el número.The form changes according to number.	Son míos.They're mine.
La forma sustituye al sustantivo.The form substitutes the noun.	¿Es tuyo? Sí, es mío.Is it yours? Yes, it's mine.

The agreement of the stressed possessives always agrees with the possessed and not with the possessor. That is why you say el mío, la mía, los míos and las mías, according to the gender and number of the noun that is omitted. This agreement sets them apart from mi, tu and su, which are unstressed forms and modify the noun directly.

IdeaIdea	ExampleExample
El masculino singular usa mío.The masculine singular uses mío.	El cuaderno es mío.The notebook is mine.
El femenino singular usa mía.The feminine singular uses mía.	La mesa es mía.The table is mine.
El plural masculino usa míos.The plural masculine uses míos.	Los libros son míos.The books are mine.
El plural femenino usa mías.The plural feminine uses mías.	Las llaves son mías.The keys are mine.

These pronouns normally go preceded by a definite article, especially in careful speech: el mío, la tuya, los suyos, las nuestras. They are not placed in front of the noun they replace, because their function is precisely to substitute it. When the noun appears, the appropriate form is no longer a possessive pronoun but a possessive adjective, as in Possessive Adjectives.

IdeaIdea	ExampleExample
Suelen ir con artículo definido.They tend to go with a definite article.	La cartera es la mía.The wallet is mine.
No preceden al sustantivo.They do not precede the noun.	El mío libro no es correcto.El mío libro no es correcto.
Sustituyen al sustantivo completo.They replace the entire noun.	Prefiero la tuya.I prefer yours.

Suyo, suya, suyos and suyas can be ambiguous because they can refer to him, her, you, them or you all. In many contexts, the ambiguity is avoided with expressions such as el de él, la de ella or los de ustedes. In Latin America, moreover, it is common to prefer su instead of vuestro, which has little use in everyday language.

IdeaIdea	ExampleExample
Suyo puede ser ambiguo.Suyo can be ambiguous.	Ese libro es suyo.That book belongs to him.
Se aclara con de más pronombre.It is clarified with de + pronoun.	Ese libro es el de él.That book is his.
Se prefiere su en gran parte de Latinoamérica.Su is preferred in much of Latin America.	Su casa está cerca.Your house is nearby.

The form lo suyo works with neutral value to talk about actions, ideas, or general situations. In this use it does not refer to a concrete object, but to a characteristic or to what corresponds to someone or something in broad terms. This neutral value helps express nuances that are also related to the Demonstrative Pronouns.

IdeaIdea	ExampleExample
Lo suyo tiene valor neutro.Lo suyo has neutral value.	Lo suyo es ayudar.What belongs to them is to help.
Se refiere a una actividad o rasgo general.It refers to a general activity or trait.	Lo suyo es cantar.What they do is sing.
No nombra un objeto concreto.It does not name a concrete object.	Lo suyo fue una buena idea.What belongs to them was a good idea.

Propio reinforces the idea of belonging or identity, but it does not replace the noun as the possessive pronouns do. Therefore it can accompany a noun, while mine, yours, or theirs take their place. In practice, these forms allow you to respond with precision and naturalness in brief exchanges such as a question about possession.

IdeaIdea	ExampleExample
Propio acompaña al sustantivo.Propio accompanies the noun.	Su propia casa es grande.One's own house is large.
El pronombre posesivo reemplaza al nombre.The possessive pronoun replaces the noun.	¿Es tuyo? Sí, es mío.Is yours? Yes, it's mine.
La concordancia sigue al objeto poseído.The agreement follows the possessed object.	La mochila es mía.The backpack is mine.