Infinitive After Prepositions | Portuguese (Portugal) Grammar

Portuguese has one rule about prepositions and verbs that is as firm as any rule in the language: a preposition is always followed by an infinitive, never by a conjugated verb. Where English freely says after eating, before leaving, by doing, for going, Portuguese reaches for the infinitive every time: depois de comer, antes de sair, fazendo, por ir. There is no preposition in the language that governs a finite (conjugated) verb — if you want a preposition and a finite verb together, you must insert a conjunction like que and use an infinitive-free structure.

This page is the tour of the most important prepositions that take an infinitive complement: de, a, para, em, por, sem, até, ao. Each has its own verbs it attaches to and its own characteristic meanings. We also look at the moment when the bare infinitive is not enough — when the subordinate clause has a new subject and you have to reach for the personal infinitive instead.

The core rule

A preposition in Portuguese cannot be followed directly by a conjugated verb. Compare:

❌ Depois eu como, vamos sair.

Incorrect — depois de takes an infinitive, not a conjugated verb.

✅ Depois de comer, vamos sair.

After eating, we're going out.

❌ Antes tu sais, fecha a porta.

Incorrect — antes de takes an infinitive (or antes que + subjunctive).

✅ Antes de saíres, fecha a porta.

Before you leave, close the door. (personal infinitive because subject is explicit)

The second correct example introduces the key refinement: when the subject of the infinitive is different from (or emphasized within) the main clause, you inflect the infinitive — producing forms like saíres, sairmos, saírem. This is the personal infinitive, treated in depth in its dedicated set of pages. On this page we focus on the prepositions themselves and give personal-infinitive forms where they are natural.

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If you have studied English, the habit of saying "after I eat" or "before you leave" with a finite verb is strong. Portuguese blocks that path entirely. Every time you see a preposition, your next verb must be an infinitive — bare if the subject is unchanged, inflected if the subject shifts.

de — the most productive preposition

De is the single most common preposition to introduce an infinitive, both after verbs that lexically require it (gostar de, acabar de, tratar de) and in time expressions (antes de, depois de).

After verbs

Many Portuguese verbs require de before a following infinitive. The de is not optional — it is part of the verb's grammatical frame, and dropping it produces ungrammatical sentences.

Gosto de ler antes de dormir.

I like to read before sleeping.

Acabei de almoçar há pouco.

I've just finished lunch.

Tenho medo de voar à noite.

I'm afraid of flying at night.

Desistimos de ir à praia por causa da chuva.

We gave up on going to the beach because of the rain.

Lembrei-me de comprar leite a caminho de casa.

I remembered to buy milk on the way home.

High-frequency verbs that take de + infinitive: gostar de (to like), acabar de (to have just / to finish), tratar de (to deal with), deixar de (to stop, to quit), esquecer-se de (to forget), lembrar-se de (to remember), ter medo de (to be afraid of), ter vergonha de (to be ashamed of), precisar de (to need), cansar-se de (to get tired of), arrepender-se de (to regret), desistir de (to give up on), depender de (to depend on).

Preciso de falar contigo um minuto.

I need to speak with you for a minute.

Esqueci-me de trazer o carregador do telemóvel.

I forgot to bring my phone charger.

Time expressions: antes de, depois de

Antes de ("before") and depois de ("after") are essentially set phrases that behave as compound prepositions.

Antes de sair, verifica se fechaste a janela.

Before leaving, check that you closed the window.

Depois de fazer a cama, tomei o pequeno-almoço.

After making the bed, I had breakfast.

When the subordinate clause has its own subject, the infinitive inflects:

Antes de tu saíres, quero dizer-te uma coisa.

Before you leave, I want to tell you something.

Depois de os miúdos adormecerem, finalmente consegui ler um livro.

After the kids fell asleep, I finally managed to read a book.

See the personal infinitive after prepositions page for the full paradigm with each preposition.

a — direction, inception, and purpose

A before an infinitive has three main uses: it introduces verbs of inception and continuation (começar a, continuar a), it marks a gerund-like progressive sense (estar a + infinitive), and it appears in a small set of idiomatic verb + a frames.

Inception and continuation

Comecei a estudar português em setembro.

I started studying Portuguese in September.

Continuo a trabalhar no mesmo projeto há dois anos.

I've been working on the same project for two years.

Os miúdos voltaram a portar-se mal na escola.

The kids started misbehaving at school again.

High-frequency verbs with a + infinitive: começar a (to start), continuar a (to continue), passar a (to start to, to take up), voltar a (to do something again), pôr-se a (to start — abrupt/colloquial), dar-se a (to devote oneself to), obrigar a (to force to).

Teaching, learning, helping

A group of verbs of instruction and assistance takes a + infinitive:

Ensinei a minha filha a andar de bicicleta no parque.

I taught my daughter to ride a bike in the park.

A avó aprendeu a usar o computador este verão.

Grandma learned to use the computer this summer.

Ajudei-o a mudar-se para o apartamento novo.

I helped him move to the new apartment.

Convidei-os a jantar lá em casa.

I invited them to have dinner at my place.

Estar a + infinitive: the European Portuguese progressive

The signature European Portuguese way of expressing an ongoing action is estar a + infinitive. This is the equivalent of Brazilian Portuguese's estar + gerund (estar comendo, estar falando).

Não posso falar agora — estou a conduzir.

I can't talk right now — I'm driving.

O que é que estás a fazer aí?

What are you doing there?

This construction is so central that it gets its own dedicated treatment in the periphrastic constructions pages. Here note only that estar a is another instance of the preposition-plus-infinitive rule: after a, the verb is never conjugated.

para — purpose, destination, deadline

Para with an infinitive marks purpose ("in order to"), destination of an action ("material for doing"), and deadlines ("by when").

Vim aqui para falar contigo sobre o Miguel.

I came here to talk to you about Miguel.

Precisamos de mais tempo para decidir.

We need more time to decide.

Tenho muito que fazer para acabar antes do fim de semana.

I have a lot to do to finish before the weekend.

When the purpose has a different subject, the personal infinitive marks it:

Deixei o jantar no forno para tu comeres quando chegares.

I left dinner in the oven for you to eat when you get home.

Para nós sabermos o preço, temos de ligar para a loja.

For us to know the price, we have to call the shop.

Para also appears in the expression pedir para + infinitive ("to ask someone to do something"), which is one of the few ways Portuguese does allow something close to "ask + person + to + verb":

Pedi aos vizinhos para não fazerem barulho depois das dez.

I asked the neighbors not to make noise after ten.

em — rare with bare infinitive, productive with personal infinitive

The preposition em ("in, on, at") is unusual: it rarely appears directly before a bare infinitive. When you see em + infinitive in modern Portuguese, it is almost always in fixed expressions or idioms.

Tenho muito prazer em conhecê-lo.

I'm very pleased to meet you. (formal)

Ela insiste em pagar a conta.

She insists on paying the bill.

Verbs that take em + infinitive: insistir em, hesitar em, ser o primeiro em, consistir em, ter prazer em, ter dificuldade em.

Tenho dificuldade em adormecer quando faz muito calor.

I have trouble falling asleep when it's very hot.

The far more productive construction is ao + infinitive, a contraction of a + o that marks simultaneous action. Morphologically ao comes from a + o (the article o), but functionally it behaves as a temporal preposition equivalent to English "upon, when, as."

Ao entrar em casa, tirei logo os sapatos.

On entering the house, I took off my shoes right away.

Ao ouvir a notícia, fiquei em choque.

Upon hearing the news, I was in shock.

With a new or emphasized subject, ao readily accepts the personal infinitive:

Ao entrarmos na sala, toda a gente se calou.

When we entered the room, everyone went quiet.

Ao saberem da decisão, os sócios ficaram furiosos.

Upon learning of the decision, the partners were furious.

The expression em vez de ("instead of") also takes an infinitive — and here, because the phrase is semantically a preposition in its own right, personal-infinitive forms are entirely natural:

Em vez de ficares em casa, anda connosco ao cinema.

Instead of staying home, come with us to the cinema.

Em vez de reclamarem, deviam ajudar-nos a resolver o problema.

Instead of complaining, they should help us solve the problem.

por — cause, means, pending action

Por has three main senses with an infinitive: cause ("because of doing"), means ("by doing"), and the distinctive por fazer idiom ("yet to be done").

Cause

Por não ter tempo, adiei a consulta para a próxima semana.

Because I didn't have time, I postponed the appointment to next week.

Fui multado por estacionar no local errado.

I was fined for parking in the wrong spot.

With a different subject, the personal infinitive marks it:

Por não saberes a resposta, não queres falar?

You don't want to speak because you don't know the answer?

Por eles chegarem sempre atrasados, vamos sair sem eles.

Because they always arrive late, we'll leave without them.

Means

Começamos por apresentar os objetivos da reunião.

We'll start by presenting the meeting's objectives.

Acabou por aceitar o convite.

He ended up accepting the invitation.

The idioms começar por ("to start by") and acabar por ("to end up") are everyday constructions. Acabar por is particularly common in colloquial speech to express "end up doing something," with a mild sense of resignation or unexpected outcome.

Por + infinitive = "yet to be done"

A distinctive Portuguese idiom: por + infinitive following a noun or adjective means the action has not yet happened — it is still pending.

Ainda tenho muita roupa por passar a ferro.

I still have a lot of clothes left to iron.

Há três capítulos por ler antes do exame.

There are three chapters left to read before the exam.

A casa está por acabar — falta pintar a sala.

The house isn't finished — the living room still needs painting.

This construction is the Portuguese equivalent of English "still to be done" or "yet to be done." It is common in everyday speech and in descriptions of work in progress. Spanish has a parallel construction (por hacer, por leer), so learners transferring from Spanish will recognize it — but do not confuse it with English for, which is not the right translation.

sem — without

Sem ("without") plus an infinitive is common, simple, and entirely predictable.

Saiu sem dizer uma palavra.

He left without saying a word. (same subject)

Acordei com uma dor de cabeça sem saber porquê.

I woke up with a headache without knowing why.

O bolo ficou na mesa toda a tarde sem ninguém tocar nele.

The cake sat on the table all afternoon without anyone touching it.

With a different subject, the personal infinitive is obligatory:

Consegui sair sem os cães ladrarem.

I managed to leave without the dogs barking.

Sem nós lhe dizermos nada, já percebeu o que se passava.

Without us telling him anything, he already figured out what was going on.

The alternative conjunction is sem que + subjunctive (imperfect or present, depending on tense), but in everyday Portuguese the preposition-plus-infinitive version dominates.

até — until

Até as a preposition means "until." With an infinitive, it marks the endpoint of an ongoing action.

Trabalhei até acabar o relatório.

I worked until I finished the report. (same subject)

Ficámos na praia até começar a chover.

We stayed at the beach until it started to rain. (generic 'it')

With a different subject, the personal infinitive takes over:

Esperámos no café até eles chegarem.

We waited at the cafe until they arrived.

Continua a insistir até ela te responder.

Keep insisting until she answers you.

Até is also used in the idiom até ao fim ("until the end") and in fixed phrases like até já ("see you soon"), but with an infinitive it is almost exclusively temporal.

When the subject matters: reaching for the personal infinitive

All of the prepositions on this page behave the same way at the syntactic boundary: if the infinitive's subject is the same as the main clause, the infinitive stays bare. If the infinitive's subject is different (or you want to emphasize who exactly is doing the action), you inflect it.

Saí sem fazer barulho.

I left without making noise. (same subject — I)

Saí sem os miúdos darem por isso.

I left without the kids noticing. (different subject — os miúdos)

Depois de comer, vamos passear.

After eating, we'll go for a walk. (same subject implied)

Depois de tu comeres, vamos passear.

After you eat, we'll go for a walk. (subject shift — you)

The endings of the personal infinitive are mercifully simple and work for every verb in the language, even the most irregular ones. The paradigm is covered in detail on the personal infinitive overview page; here it is in miniature for chegar:

Subject	Personal infinitive
eu	chegar
tu	chegares
ele / ela / você	chegar
nós	chegarmos
eles / elas / vocês	chegarem

Add these endings after any preposition when the subject is not the same as the main clause's subject, and you will produce native-sounding Portuguese.

The contrast with English

English can say "after I eat," "before you leave," "because she didn't call" — all with conjunctions and finite verbs. English also allows gerunds after prepositions: "after eating, before leaving, without saying." Portuguese has neither option. There are no preposition + finite verb combinations, and there is no gerund that behaves like English's -ing form in this context (Portuguese gerunds exist but are used for simultaneous action, not as prepositional complements). The infinitive does all the work.

English	Portuguese
after eating	depois de comer
before leaving	antes de sair
without saying a word	sem dizer uma palavra
by working hard	trabalhando muito / por trabalhar muito
for knowing the answer	por saber a resposta
until leaving	até sair
because of not having time	por não ter tempo

The pattern is clean: whenever English uses an -ing or a gerund-like form after a preposition, Portuguese uses the plain infinitive (or personal infinitive with a different subject).

The contrast with Spanish

Spanish behaves nearly identically to Portuguese here — both languages require the infinitive after a preposition — with one major difference: Spanish has no personal infinitive. Where Portuguese can say para nós sabermos, Spanish must either leave the subject ambiguous (para saber, context-dependent) or build a full para que + subjuntivo clause (para que sepamos). Portuguese speakers reach for the personal infinitive constantly; Spanish speakers do not have this option.

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A Spanish speaker learning Portuguese will correctly use bare infinitives after prepositions from day one — that part transfers cleanly. The skill to build is the moment of recognition: "here the subject is different — I can inflect the infinitive instead of reaching for a que clause." That moment is what turns Portuguese from Spanish-with-extra-accents into a language you actually speak.

Common Mistakes

❌ Gosto muito Lisboa.

Incorrect — gostar requires de before its object or complement.

✅ Gosto muito de Lisboa.

I really like Lisbon.

✅ Gosto de passear pelas ruelas.

I like walking through the alleys.

The preposition de is obligatory after gostar. Dropping it is one of the most frequent errors of English and Spanish speakers (Spanish has me gusta + noun without preposition, which causes the transfer error).

❌ Depois de eu chego, ligamos à tua mãe.

Incorrect — a preposition cannot govern a conjugated verb. Use an infinitive.

✅ Depois de eu chegar, ligamos à tua mãe.

After I arrive, we'll call your mom.

✅ Depois de chegar, ligamos à tua mãe.

After I arrive, we'll call your mom. (subject inferred)

Depois de takes an infinitive, full stop. If you have a subject pronoun in place, the infinitive can either stay bare (eu chegar, because the 1sg form is identical to the infinitive) or inflect for other persons (tu chegares, nós chegarmos, eles chegarem). It can never take a conjugated finite verb.

❌ Comecei estudar português em setembro.

Incorrect — começar takes a before an infinitive complement.

✅ Comecei a estudar português em setembro.

I started studying Portuguese in September.

Começar always takes a before an infinitive. The same applies to continuar a, voltar a, aprender a, ensinar a. Dropping the preposition is a direct transfer from English or Spanish (empecé a estudiar has a, but empezé estudiando with a gerund does not).

❌ Antes que saíres, fecha a porta.

Incorrect — antes que takes a subjunctive, not a personal infinitive.

✅ Antes de saíres, fecha a porta.

Before you leave, close the door. (preposition + personal infinitive)

✅ Antes que saias, fecha a porta.

Before you leave, close the door. (conjunction + present subjunctive)

Antes de (preposition) takes the infinitive; antes que (conjunction) takes the subjunctive. Mixing the two — conjunction + infinitive — is ungrammatical.

❌ Estou comendo agora.

Brazilian Portuguese, not European. In PT-PT, use estar a + infinitive.

✅ Estou a comer agora.

I'm eating right now.

The progressive form in European Portuguese is estar a + infinitive, not estar + gerund. The gerund form is Brazilian; using it in Portugal will mark you as a Brazilian speaker (not wrong, but not PT-PT). This is one of the clearest differences between the two varieties.

Key takeaways

Every Portuguese preposition takes an infinitive, never a conjugated verb. This is an absolute rule.
De is the most productive preposition with infinitives — many lexical verbs require it (gostar de, precisar de, acabar de, lembrar-se de).
A introduces aspectual verbs (começar a, continuar a, voltar a), instruction verbs (ensinar a, ajudar a, aprender a), and the progressive estar a + infinitive.
Para marks purpose and deadline; it takes the personal infinitive readily when the subject shifts.
Em rarely takes a bare infinitive (mostly in set phrases like ter dificuldade em, insistir em); it shines as ao + infinitive, the simultaneous-action construction.
Por means "because of" (cause), "by means of" (agency), and — distinctively — "yet to be done" (pending action: roupa por passar, três capítulos por ler).
Sem and até are simple temporal/circumstantial prepositions — always infinitive, personal when the subject shifts.
When the subject of the infinitive clause is different from (or emphasized within) the main clause, reach for the personal infinitive. This is a B1 skill with an A2 foundation; see the personal infinitive pages for deep coverage.