Position of object pronouns

Voy a llamarte mañana.I'll call you tomorrow.

An object or reflexive pronoun — me, te, se, lo/la, nos, os, los/las, le/les — doesn't always sit in the same place. With a single conjugated verb it goes right before it, but with an infinitive, a gerund, or an affirmative command, Spanish gives it other options — or takes away the choice entirely.

Quick shortcut: before a single conjugated verb, the pronoun goes in front. With an infinitive or a gerund, it can go before the whole construction or attach to the end — both are correct. With an affirmative command, it must attach to the end.

Before the verb: the default

With one conjugated verb — in any tense, and in questions or negatives too — the pronoun goes right before it:

Te veo. (I see you.) Lo compro. (I buy it.) No te veo. (I don't see you.) ¿Lo compraste? (Did you buy it?)

This is also true for negative commands: No lo compres. (Don't buy it.) — never No cómpralo or No compres lo. (For the forms themselves, see Direct object pronouns, Indirect object pronouns and Reflexive verbs, which follow this same placement rule.)

Two positions with an infinitive

In many common verb-plus-infinitive constructions — ir a, querer, poder, modal verbs and several more like them — the pronoun can go before the conjugated verb or attach to the end of the infinitive. Both are equally correct and mean exactly the same thing. (This option is tied to specific constructions like these, not to every verb that happens to be followed by an infinitive.)

Lo voy a comprar. = Voy a comprarlo. (I'm going to buy it.) Te quiero ayudar. = Quiero ayudarte. (I want to help you.)

More on this construction is in Ir a + infinitive.

Two positions with a gerund

The same two-position choice applies to estar + gerundio (the present continuous):

Lo estoy comprando. = Estoy comprándolo. (I'm buying it.)

The accent on comprándolo is no accident — attaching a pronoun to a gerund always adds one. Here's why: a gerund like comprando is already stressed on its -ando/-iendo syllable (com-pran-do), and because the word ends in a vowel, that stress already falls exactly where Spanish spelling expects it by default — no written accent needed. Attach lo, though, and the word grows by a syllable (com-pran-do-lo): the stress hasn't moved, but the default stress position has, since it's now expected on the new next-to-last syllable (-do-). Whenever the real stress falls further back than that — the third-from-last syllable or earlier — Spanish marks it with a written accent, no matter what the word is. That's the same rule behind words like rápido or teléfono, just triggered here by attaching a pronoun.

The estar + gerundio forms themselves are in Present continuous.

Always attached: affirmative commands

With an affirmative command, there's no choice — the pronoun always attaches to the end:

Cómpralo. (Buy it.) Ayúdame. (Help me.) Dime. (Tell me.)

The same written-accent rule from above decides whether an accent mark is needed: compra is already stressed where the default rule expects (COM-pra, penultimate syllable, ends in a vowel), but attaching -lo pushes that same stressed syllable one further back, past what the new ending now expects by default — so it needs an accent: cómpralo. A short command like pon (from poner) doesn't have this problem: pon + te = ponte is still stressed on the new next-to-last syllable exactly where the default rule expects, so no accent is needed. Specific forms appear in Affirmative tú commands.

Common mistakes

• ❌ Estoy lo comprando. → ✅ Lo estoy comprando. / Estoy comprándolo. (the pronoun can't float unattached between estoy and the gerund — it either comes before estoy or attaches to the gerund.)
• ❌ Compra lo. → ✅ Cómpralo. (an affirmative command's pronoun must attach, as one written word, with an accent if the stress needs it.)
• ❌ No cómpralo. → ✅ No lo compres. (a negative command goes back to the normal position, before the verb, unattached.)

Quick check

1. Rewrite two ways: Voy a leer el libro. → replace el libro with lo, both before and attached.
2. Estoy escribiendo la carta. → replace la carta with la, both before and attached.
3. Give an affirmative command from ayudar + me ("help me").
4. Correct this: No ayúdame.

Key takeaways

• Before a single conjugated verb — including in negatives and negative commands — the pronoun always goes in front, unattached: Lo compro., No lo compres.
• In common verb-plus-infinitive constructions like ir a, and with a gerund, the pronoun can go before the whole construction or attach to the end: Lo voy a comprar. = Voy a comprarlo.; Lo estoy comprando. = Estoy comprándolo.
• With an affirmative command, the pronoun must attach to the end: Cómpralo., Ayúdame.
• Attaching a pronoun to a gerund or a command adds a written accent whenever the real stress ends up further back than the new default stress position — the same general Spanish accent rule used everywhere else, not a special case just for pronouns.