Italian uses three auxiliary verbs — avere, essere, and stare — to build the compound parts of its verb system. Each combines with a non-finite form (a past participle or a gerund) to create a tense or aspect that the auxiliary alone cannot express. The decisions you make about auxiliaries are among the most important in the language: they shape the form, the meaning, and even the agreement of every compound construction.
This page introduces the three auxiliaries, what each one builds, and why the choice between avere and essere is arguably the single most consequential grammatical decision in Italian beyond getting the verb form to agree with the subject.
What an auxiliary does
An auxiliary verb (Italian: verbo ausiliare) is a verb that helps another verb form a tense, mood, or aspect. By itself, the auxiliary contributes only the grammatical scaffolding (person, number, time); the lexical meaning comes from the verb that follows. Ho on its own means "I have" — a possession verb. But ho mangiato means "I ate" or "I have eaten," and the ho there is contributing nothing about possession; it is just signalling "first person singular, completed action."
Italian has three auxiliaries, each pairing with a particular non-finite form:
| Auxiliary | Combines with | Builds | Example |
|---|---|---|---|
| avere | past participle | compound indicative tenses (transitive verbs) | ho mangiato (I ate) |
| essere | past participle | compound indicative tenses (intransitive motion / change-of-state / reflexive) | sono andato (I went) |
| stare | gerund | progressive aspect | sto leggendo (I'm reading) |
| stare | per + infinitive | imminent future | sto per uscire (I'm about to go out) |
Each of these constructions does work that no single conjugated form can do alone. The compound tenses give Italian a way to mark completed action; the progressive lets it mark currently in progress action; the stare per construction lets it mark immediately upcoming action.
avere + past participle: most compound tenses
When the verb is transitive (takes a direct object), the auxiliary in compound tenses is avere. This is by far the most common case, because most Italian verbs are transitive.
Ho mangiato una pizza enorme ieri sera.
I ate a huge pizza last night. (mangiare transitive → avere)
Hai visto il mio cellulare? L'ho cercato dappertutto.
Have you seen my phone? I've looked for it everywhere. (vedere and cercare both transitive)
Avevamo già finito il lavoro quando sei arrivato.
We had already finished the work when you arrived. (trapassato prossimo with avere)
Avrò sicuramente dimenticato qualcosa di importante.
I will surely have forgotten something important. (futuro anteriore with avere)
The same auxiliary builds every compound indicative tense — passato prossimo (ho mangiato), trapassato prossimo (avevo mangiato), futuro anteriore (avrò mangiato), congiuntivo passato (che io abbia mangiato), congiuntivo trapassato (che io avessi mangiato), and the very rare trapassato remoto (ebbi mangiato) — and the same for the conditional perfect (avrei mangiato).
Participle agreement with avere: the lo/la/li/le/ne rule
By default, the past participle after avere does not agree with anything; it stays in its base masculine singular form (-ato, -uto, -ito). However, there is an important exception: when a third-person direct-object pronoun (lo, la, li, le, ne) precedes the auxiliary, the participle agrees with that pronoun in gender and number.
Ho letto il libro.
I read the book. (no preceding pronoun → participle stays in -o)
L'ho letto.
I read it (m.). (lo + ho elide; participle still -o)
L'ho letta.
I read it (f.). (la + ho elide; participle now -a, agreeing with the feminine la)
Le ho lette tutte in un giorno.
I read them (f.pl.) all in one day. (le + ho; participle agrees as -e)
Ne ho lette tre.
I read three of them. (ne refers to feminine plural; participle agrees)
This is the only systematic case where the participle agrees in avere-constructions. With direct-object nouns (ho letto le lettere), no agreement happens — only with the preceding pronoun. For more on this delicate rule, see Participle Agreement in Compound Tenses.
essere + past participle: intransitive motion, change of state, reflexive
Some intransitive verbs use essere as their auxiliary instead of avere. The verbs that take essere fall into three main groups:
- Verbs of motion to/from a destination: andare, venire, arrivare, partire, tornare, salire, scendere, entrare, uscire, cadere, scappare.
- Verbs of change of state or existence: nascere, morire, diventare, crescere, invecchiare, ingrassare, dimagrire, apparire, sparire, succedere, accadere, restare, rimanere.
- All reflexive and reciprocal verbs: alzarsi, lavarsi, vestirsi, divertirsi, sposarsi, incontrarsi, sentirsi.
A handful of common copulas also take essere: essere itself, stare (when used as a copula), piacere, sembrare, parere, bastare, mancare, servire, toccare.
Sono andata al lavoro a piedi stamattina.
I went to work on foot this morning. (andare + essere; participle agrees with feminine subject)
I miei nonni sono nati in Sicilia.
My grandparents were born in Sicily. (nascere + essere; participle agrees as m.pl.)
Marco si è alzato alle sei per prendere il treno.
Marco got up at six to catch the train. (alzarsi reflexive → essere)
Mi è piaciuto moltissimo quel film.
I really liked that film. (piacere + essere)
Participle agreement with essere
This is critical: the past participle of an essere-verb always agrees with the subject in gender and number, just like an adjective.
| Subject | Compound form of "to go" |
|---|---|
| io (m.) | sono andato |
| io (f.) | sono andata |
| tu (m.) | sei andato |
| tu (f.) | sei andata |
| lui | è andato |
| lei | è andata |
| noi (m. or mixed) | siamo andati |
| noi (f.) | siamo andate |
| voi (m. or mixed) | siete andati |
| voi (f.) | siete andate |
| loro (m. or mixed) | sono andati |
| loro (f.) | sono andate |
Le mie amiche sono partite per Parigi.
My (female) friends left for Paris. (partite, f.pl., agrees with le mie amiche)
Carla e Marco si sono sposati l'estate scorsa.
Carla and Marco got married last summer. (mixed-gender plural defaults to masculine sposati)
This agreement is not optional. Sono andato (m.) and sono andata (f.) are not interchangeable — they tell the listener the speaker's gender. For mixed-gender plurals, the masculine wins, as in most Romance languages.
How to choose: avere or essere?
The basic decision tree:
- Does the verb take a direct object? If yes, use avere.
- Is it a reflexive verb (with mi, ti, si, ci, vi, si attached)? If yes, use essere.
- Does the verb express motion to/from a destination, or a change of state? If yes, use essere.
- Otherwise, default to avere.
This handles the vast majority of cases. The remaining tricky ones are:
- The dual-auxiliary verbs (correre, cambiare, finire, passare, salire, scendere, vivere), which take essere when intransitive and avere when transitive (see Transitive and Intransitive Verbs).
- A handful of intransitive verbs that take avere even though they don't have direct objects: dormire, camminare, lavorare, ridere, piangere, mentire, viaggiare, nuotare, parlare, telefonare.
Ho dormito otto ore.
I slept for eight hours. (intransitive but takes avere — it's not motion or change of state)
Abbiamo camminato per tre chilometri.
We walked for three kilometres. (intransitive activity → avere)
Hanno parlato tutta la sera al telefono.
They talked all evening on the phone.
These verbs are intransitive activities that don't fit the motion-to-destination or change-of-state pattern, so they go with the default avere. For the full decision tree, see Auxiliary Choice with Compound Tenses.
stare + gerundio: the progressive
When you want to emphasise that an action is currently in progress, Italian uses stare + gerundio. The gerund is formed with -ando for -are verbs and -endo for -ere and -ire verbs.
Sto leggendo un romanzo molto interessante.
I'm reading a very interesting novel. (right now, in progress)
Cosa stai facendo? — Sto cucinando la cena.
What are you doing? — I'm cooking dinner.
Stavano dormendo quando è arrivato il pacco.
They were sleeping when the package arrived. (imperfect progressive)
This construction is much narrower than the English progressive. English uses "be + -ing" for many things — habitual actions in the present period (I'm working in Rome these days), planned future actions (I'm flying to Milan tomorrow), descriptions of states (I'm hoping to hear from you). Italian uses stare + gerundio essentially only for actions happening at this very moment or, in the past, at that very moment in the narrative.
In questo momento sto guardando un film.
Right now I'm watching a film.
Lavoro a Roma.
I work in Rome / I'm working in Rome (these days). (English progressive → Italian simple present)
Domani parto per Milano.
Tomorrow I'm leaving for Milan. (English progressive for planned future → Italian simple present)
The simple present in Italian covers a much wider range than the English simple present, so the progressive is reserved for genuinely ongoing actions. For more on this restriction, see Overusing the stare + gerundio Construction.
stare per + infinitive: imminent future
A second use of stare is to express that something is about to happen. The construction is stare per + infinitive.
Sto per uscire, ti chiamo dopo.
I'm about to go out, I'll call you later.
Il treno sta per partire, sbrigati!
The train is about to leave, hurry up!
Stavo per dirtelo quando sei arrivato.
I was about to tell you when you arrived. (imperfect — was about to)
This construction is extremely useful and has no exact equivalent in any one English form — "about to," "on the verge of," "any moment now." Whenever you want to convey that an event is imminent, stare per is the natural choice.
Why the auxiliary decision matters so much
A learner who consistently picks the right auxiliary in Italian sounds dramatically more fluent than one who does not. There are three reasons:
- Frequency: every compound tense uses an auxiliary, and compound tenses are constant in everyday speech. The passato prossimo alone is the workhorse past tense in Northern Italy.
- Visibility: an error in auxiliary choice is audible. Ho andato sounds wrong to every native ear; it is on a par with English "I goed" — instantly identifiable as foreign.
- Cascading consequences: the auxiliary you choose determines whether you have to make the participle agree with the subject (essere), or only with a preceding direct-object pronoun (avere). Get the auxiliary wrong and the whole compound construction unravels.
A note on modal verbs (potere, dovere, volere)
When potere, dovere, volere are used with an infinitive, the auxiliary in compound tenses depends on the infinitive that follows.
- Ho dovuto lavorare fino a tardi (I had to work late) — lavorare is intransitive but takes avere, so dovere takes avere.
- Sono dovuto andare in ufficio (I had to go to the office) — andare takes essere, so dovere takes essere.
Ieri sera non ho potuto venire alla festa perché ho dovuto lavorare.
Last night I couldn't come to the party because I had to work. (potuto + venire would normally take essere, but in modern colloquial Italian avere is increasingly tolerated; here lavorare clearly takes avere)
Sono voluta tornare a casa presto perché ero stanca.
I wanted to go back home early because I was tired. (tornare → essere; voluta agrees with the feminine subject)
In modern colloquial Italian, avere is often used with modals + intransitive infinitives (ho dovuto andare) — purists prefer essere (sono dovuto andare). For the prescriptive rules, see Auxiliary Choice with Modals.
Common mistakes
❌ Ho andato al supermercato dopo il lavoro.
Incorrect — andare takes essere.
✅ Sono andato al supermercato dopo il lavoro.
I went to the supermarket after work.
❌ Sono mangiato troppa pasta a pranzo.
Incorrect — mangiare is transitive and takes avere.
✅ Ho mangiato troppa pasta a pranzo.
I ate too much pasta at lunch.
❌ Maria è andato al cinema.
Incorrect — with essere, the participle must agree with the subject.
✅ Maria è andata al cinema.
Maria went to the cinema.
❌ Marco si ha alzato presto stamattina.
Incorrect — reflexive verbs always take essere.
✅ Marco si è alzato presto stamattina.
Marco got up early this morning.
❌ Sto lavorando in Italia da tre anni.
Incorrect (or at least very unidiomatic) — Italian uses simple present for ongoing periods, not the progressive.
✅ Lavoro in Italia da tre anni.
I've been working in Italy for three years.
❌ Le ho letto tutte in una notte.
Incorrect — when le precedes avere, the participle agrees as -e.
✅ Le ho lette tutte in una notte.
I read them all in one night.
Key takeaways
- Italian has three auxiliary verbs: avere, essere, and stare.
- Avere + past participle builds compound tenses for transitive verbs and most intransitive activity verbs. The participle does not agree with anything except a preceding direct-object pronoun (lo, la, li, le, ne).
- Essere + past participle builds compound tenses for verbs of motion/change of state, copulas, and all reflexive verbs. The participle always agrees with the subject.
- Stare + gerundio builds the progressive aspect, used much more narrowly than the English progressive — only for actions happening right now.
- Stare per + infinitive expresses imminent future ("about to").
- Choosing the right auxiliary is one of the most important decisions in Italian grammar; errors here are immediately audible.
Now practice Italian
Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.
Open the Italian course →Related Topics
- Transitive and Intransitive VerbsA2 — Why the transitive/intransitive distinction matters more in Italian than in English: it determines the auxiliary in compound tenses and shapes how you build sentences.
- Copulative Verbs: essere, stare, diventare, sembrare, parereA2 — The verbs that link a subject to a predicate noun or adjective in Italian — and how the adjective then agrees with the subject through the verb.
- Auxiliary Selection: Essere vs Avere (The Critical Decision)A1 — The single grammatical decision that determines how every Italian compound tense works — when to use essere, when to use avere, and how to predict the right answer for any verb.
- Participle Agreement RulesA2 — The three scenarios that govern how Italian past participles agree (or stay frozen) in compound tenses — with the preceding-clitic rule that trips up almost every learner.
- Il Passato Prossimo: OverviewA1 — Italian's primary past tense for completed actions — how to form it, why the auxiliary choice (avere vs essere) is the most consequential decision, and where it fits in modern Italian.
- Gerundio with Stare: The ProgressiveA1 — Italian's stare + gerundio construction — when to use it, when NOT to use it (most of the time, actually), and why English speakers reach for it far too often.