What order do Spanish object pronouns go in?

Indirect object pronoun first, then direct object pronoun, then the verb: me lo da (he gives it to me). The indirect (me, te, le/se, nos, os, les/se) always comes before the direct (lo, la, los, las). A useful memory hook is RID - Reflexive, Indirect, Direct - for the full order including reflexive pronouns, but for the common two-pronoun case it is simply indirect before direct.

Why does 'le lo' become 'se lo'?

Spanish refuses to put two pronouns starting with l next to each other. When the indirect le or les would come before a direct lo, la, los or las, the le/les changes to se. So 'I give it to him' is se lo doy, never le lo doy. The se here is not reflexive; it is a disguised le or les, which is why se lo doy can mean 'I give it to him, to her, to you or to them'.

When do pronouns attach to the verb and when do they go before it?

Before a conjugated verb they go in front as separate words: me lo da. With an infinitive, a gerund or an affirmative command they attach to the end as one word: dármelo, dándomelo, dámelo. With a verb-plus-infinitive structure both positions are allowed: te lo voy a dar or voy a dártelo. Attaching usually forces a written accent to keep the stress where it was.

Spanish Pronoun Order

Once you can use object pronouns one at a time, the next step is stacking two of them: "he gives it to me" becomes me lo da. Spanish handles this with three rules that never bend. Learn them as a block.

Rule 1: indirect before direct

When you have both an indirect object pronoun and a direct object pronoun, the indirect always comes first, then the direct, then the verb.

Me lo da. (He gives it (direct) to me (indirect).) - indirect me, then direct lo.
Te la escribo. (I'll write it to you.) - indirect te, then direct la.
Nos los manda. (He sends them to us.)

The full order, including reflexive pronouns, is RID: Reflexive, Indirect, Direct. For most sentences you only juggle the indirect and direct, so the working rule is simply: indirect before direct.

Indirect (1st)	Direct (2nd)	Verb	Meaning
me	lo / la	da	he gives it to me
te	los / las	doy	I give them to you
se (= le)	lo / la	digo	I say it to him/her
nos	lo / la	trae	he brings it to us
os	los / las	mando	I send them to you
se (= les)	lo / la	explico	I explain it to them

Rule 2: le and les become se before lo, la, los, las

Spanish will not allow two pronouns that both begin with l to sit side by side. So when the indirect le or les would land in front of the direct lo, la, los, las, the le/les changes to se.

le lo doy is impossible -> se lo doy (I give it to him/her/you).
les la mando is impossible -> se la mando (I send it to them).

This se is not the reflexive se. It is a stand-in for le or les, which is why a sentence like se lo doy is ambiguous on its own: it can mean "to him", "to her", "to you (formal)" or "to them". If you need to pin it down, add the clarifying phrase:

Se lo doy a él. (I give it to him.)
Se lo doy a ellos. (I give it to them.)

Rule 3: position - before the verb or attached to it

The pronoun pair has two possible homes, depending on the verb form.

Before a conjugated verb - they go in front, as two separate words:

Me lo da. (He gives it to me.)
No te la doy. (I'm not giving it to you.) - in the negative, the no comes before the pronouns.

Attached to the end of an infinitive, a gerund, or an affirmative command - they become one word:

Infinitive: Quiero dártelo. (I want to give it to you.)
Gerund: Está dándomelo. (He is giving it to me.)
Affirmative command: Dámelo. (Give it to me.)

Negative commands keep the pronouns in front, separate: No me lo des (don't give it to me).

Verb + infinitive structures allow both, your choice:

Te lo voy a dar. = Voy a dártelo. (I'm going to give it to you.)
Me lo está diciendo. = Está diciéndomelo. (He is telling it to me.)

The accent you add when attaching

When you attach pronouns to the end of a verb, the word gets longer but the spoken stress must stay where it was. Spanish marks this with a written accent.

da -> dámelo (the stress stays on da, so it needs an accent once two syllables are added).
escribe -> escríbemela (write it to me).
dar -> dártelo (the stress stays on the final dar; with one pronoun darme needs no accent, but the rhythm shifts as you add more).
diciendo -> diciéndomelo (the stress stays on cien).

The rule of thumb: attaching one pronoun to an infinitive often needs no accent (darme, decirte); attaching two, or attaching to a command or gerund, almost always does (dámelo, diciéndomelo).

Worked examples

¿El libro? Te lo presto. (The book? I'll lend it to you.) - indirect te, direct lo.
¿Las llaves? Se las di a tu madre. (The keys? I gave them to your mother.) - le -> se before las.
No quiero decírtelo. (I don't want to tell it to you.) - attached to the infinitive, accent on dec.
Cómpramelo, por favor. (Buy it for me, please.) - affirmative command, attached, accent added.
No se lo digas. (Don't tell it to him.) - negative command, pronouns in front, le -> se.

The mistakes English speakers make

Putting the direct pronoun first. English says "give it to me", and learners copy that order with lo me da. Spanish is the other way round: indirect first, me lo da.

Saying "le lo". The most common written error. Whenever you see le or les about to meet lo, la, los, las, switch the le/les to se: se lo doy, never le lo doy.

Forgetting the accent when attaching. Damelo without the accent is wrong; the stress would drift to the wrong syllable, so it must be dámelo. The accent is not decoration, it preserves the pronunciation.

Attaching to a negative command. No démelo is wrong. Negative commands keep the pronouns in front: no me lo des. Only affirmative commands take attached pronouns.