Relative clauses come in two flavours that look almost identical on the page but mean very different things: restrictive (also called defining) and non-restrictive (also called non-defining or parenthetical). A restrictive clause narrows down which specific person or thing you mean — it is essential to the identification. A non-restrictive clause merely adds extra information about something already fully identified; remove it and the sentence still picks out the same referent. In Portuguese, as in English, the distinction is marked chiefly by commas — but the commas are not cosmetic. They change the meaning. Getting this right is a B1-level skill that separates writers who are thinking about what they say from those who are merely translating word-for-word.
The core distinction
Consider these two sentences:
Os meus alunos *que estudam muito passam no exame. Os meus alunos, **que estudam muito, passam no exame.*
They differ by a pair of commas. The first says: "Those of my students who study a lot pass the exam" — implying that some students do not study a lot, and those do not necessarily pass. The clause restricts which students I am talking about. The second says: "My students — and by the way, all of them study a lot — pass the exam." The clause is parenthetical, an aside; it does not narrow down which students, it comments on them.
Os meus alunos que estudam muito passam no exame.
My students who study a lot pass the exam. (restrictive — only the studious ones)
Os meus alunos, que estudam muito, passam no exame.
My students, who all study a lot, pass the exam. (non-restrictive — all my students, and incidentally they all study)
This is the whole secret. Two commas — or no commas — change a sentence from a qualification to a comment. English works the same way, but English writers are often careless about commas, so you may have absorbed a habit of treating them as optional. In Portuguese they are not optional: omitting or inserting a pair of commas changes what you are asserting.
Restrictive clauses — essential, no commas
A restrictive relative clause is a filter. It takes a noun that could refer to many things and narrows it down to a specific subset — the one or ones you mean. Without the clause, the sentence would be too vague or mean something different.
O livro que comprei ontem é fantástico.
The book I bought yesterday is fantastic. (which book? the one I bought yesterday)
A casa onde cresci já não existe.
The house where I grew up no longer exists. (which house? the one where I grew up)
Preciso do ficheiro que te enviei por email.
I need the file that I sent you by email.
Os miúdos que jogam no pátio são do terceiro ano.
The kids who are playing in the yard are in year three.
A caneta com que escrevo esta carta foi do meu avô.
The pen I'm writing this letter with belonged to my grandfather.
In each of these, strip out the relative clause and the sentence becomes either meaningless or changes its meaning. "O livro é fantástico" — which book? "Os miúdos são do terceiro ano" — which kids? The relative clause is doing indispensable work.
Why no commas?
Think of the commas as spoken pauses. When a clause is essential — when you could not understand the sentence without it — you would not pause before it. You would speak the whole phrase in a single breath: o livro que comprei ontem. The absence of commas reflects the absence of that pause.
Non-restrictive clauses — parenthetical, set off by commas
A non-restrictive relative clause is extra information about something already identified. The main clause stands on its own; the relative clause is a bonus comment, an aside, a parenthesis. You can remove it and the sentence still names the same entity.
O meu irmão, que mora em Coimbra, vem passar o Natal connosco.
My brother, who lives in Coimbra, is coming to spend Christmas with us.
Lisboa, que foi capital do império, está cheia de história.
Lisbon, which was the capital of the empire, is full of history.
A Maria, que conheço desde a infância, casa-se no próximo mês.
Maria, whom I've known since childhood, is getting married next month.
O novo Código do Trabalho, que foi aprovado em dezembro, entra em vigor em abril.
The new Labour Code, which was approved in December, comes into effect in April.
Remove the clause from each sentence and notice what happens:
- O meu irmão vem passar o Natal connosco. — Still identifies the same brother (I only have one, or the context makes it clear).
- Lisboa está cheia de história. — Lisboa is already uniquely identified; the clause does not narrow it down.
- A Maria casa-se no próximo mês. — Again, a Maria is the particular Maria we are talking about.
The clause added colour but not identification. That is the signature of a non-restrictive clause.
O meu pai, que é médico, vai dar uma palestra amanhã.
My father, who is a doctor, is giving a talk tomorrow. (I only have one father)
O Porto, que visitei pela primeira vez em 2015, é a minha cidade favorita.
Porto, which I first visited in 2015, is my favourite city.
Why the commas?
The commas are the written equivalent of the pauses you would make in speech. Read the sentences aloud: "O meu irmão... que mora em Coimbra... vem passar o Natal connosco." You naturally drop your voice and pause around the aside. Portuguese writing formalises this with commas.
The meaning shift — the same words, two readings
The power of this distinction is that many sentences are grammatically ambiguous without the commas. The writer chooses which reading to force on the reader by inserting or omitting commas.
Consider:
Os passageiros que tinham crianças embarcaram primeiro.
The passengers who had children boarded first. (only those with children — restrictive)
Os passageiros, que tinham crianças, embarcaram primeiro.
The passengers, who (all) had children, boarded first. (all passengers, and they all had children — non-restrictive)
The first sentence implies there were also passengers without children, and those boarded later. The second sentence implies every passenger had children. A lawyer drafting a contract, a journalist drafting a report, a novelist drafting a description — all of them have to choose between these readings, and the choice is made by commas.
Os funcionários que chegaram atrasados perderam o bónus.
The employees who arrived late lost the bonus. (only the late ones — restrictive)
Os funcionários, que chegaram atrasados, perderam o bónus.
The employees, who arrived late, lost the bonus. (all the employees, and they all arrived late — non-restrictive)
This contrast scales up to serious consequences. "Os médicos que não vacinaram os filhos devem ser investigados" targets a specific subgroup. "Os médicos, que não vacinaram os filhos, devem ser investigados" accuses every doctor in question of not vaccinating their children. The two sentences are not equivalent — they are nearly opposite in implication.
Which relative pronouns can be used?
Both kinds of clauses can be built with most of the relative pronouns. But there is a major difference in how flexibly o qual / a qual / os quais / as quais can be used.
Restrictive clauses
In restrictive clauses, que is the overwhelming default. Quem appears after prepositions (for people). O qual is rare and sounds very formal or stilted in restrictive contexts — most native writers avoid it in everyday restrictive clauses.
O livro que comprei foi caro.
The book I bought was expensive. (natural)
O livro o qual comprei foi caro.
The book which I bought was expensive. (grammatical but stiff — que is preferred)
Non-restrictive clauses
In non-restrictive clauses, o qual is much more at home. It is a stylistic choice: using o qual instead of que marks the clause as formal, often as written rather than spoken register. It is also often used to disambiguate when two possible antecedents precede the relative pronoun.
O João, o qual conheço há anos, chegou ontem a Lisboa.
João, whom I've known for years, arrived in Lisbon yesterday. (o qual — formal, written feel)
O João, que conheço há anos, chegou ontem a Lisboa.
João, whom I've known for years, arrived in Lisbon yesterday. (que — neutral)
Both are correct. The version with o qual would be more typical in a newspaper article or a formal written biography; the version with que in a casual email or a conversation retold.
Disambiguation — where o qual shines
Look at this sentence:
Falei com a irmã do João, *que vive em Paris.*
Who lives in Paris — the sister or João? Portuguese (like English) leaves this technically ambiguous with que. Using o qual / a qual fixes the ambiguity, because the pronoun agrees in gender with its antecedent.
Falei com a irmã do João, a qual vive em Paris.
I spoke with João's sister, who (the sister — feminine) lives in Paris.
Falei com a irmã do João, o qual vive em Paris.
I spoke with João's sister, who (João — masculine) lives in Paris.
This is one of the main reasons educated written Portuguese favours o qual in non-restrictive clauses. It is a precision tool, not a pomposity.
Proper names and unique referents
Proper names (Maria, João, Lisboa, o Tejo) and nouns that refer to something unique (o sol, a minha mãe) almost always take non-restrictive clauses, because they are already fully identified.
A Ana, que é a minha colega de trabalho, convidou-me para o casamento.
Ana, who is my colleague, invited me to the wedding.
O Tejo, que atravessa Lisboa, desagua no Atlântico.
The Tagus, which crosses Lisbon, flows into the Atlantic.
A minha mãe, que tem oitenta anos, ainda conduz todos os dias.
My mother, who is eighty, still drives every day.
Writing "A Ana que é a minha colega convidou-me" (no commas) would be very odd — it would suggest there are multiple Anas and you are distinguishing the colleague one from others. Sometimes that is exactly what you mean ("the Maria who works in accounting, not the Maria in marketing"), but it requires a specific context.
A Maria que trabalha na contabilidade é irmã dela.
The Maria who works in accounting is her sister. (restrictive — distinguishing among multiple Marias)
Intonation in speech
In spoken Portuguese, the comma distinction is rendered as an intonational contour. A non-restrictive clause is uttered with:
- A slight pause before and after
- A lower pitch on the clause itself (as if muted or backgrounded)
- A return to the main contour after the clause
Listen to a Portuguese newsreader: "O Presidente da República... que hoje se deslocou ao Porto... anunciou medidas..." The clause is almost whispered relative to the surrounding material.
A restrictive clause, by contrast, is spoken at the same pitch and rhythm as the surrounding material — no pause, no drop:
"O livro que comprei ontem está na mesa." — One continuous phrase.
Training your ear to this contour will help you produce the commas correctly in writing too.
Register and style considerations
- Journalistic writing uses non-restrictive clauses heavily to pack biographical or contextual information: "Mário Soares, que foi Primeiro-Ministro e Presidente..."
- Academic writing uses both freely, often with o qual in non-restrictive clauses for precision.
- Conversational speech uses restrictive clauses often and non-restrictive clauses rarely — in conversation, we tend to split long non-restrictive clauses into separate sentences. Instead of "O meu colega, que mora em Braga, vem cá amanhã," we often say "O meu colega vem cá amanhã. Ele mora em Braga, sabes?"
- Legal writing is militant about the restrictive/non-restrictive distinction because the commas can change contractual obligations.
O professor que me orientou a tese foi galardoado com um prémio.
The professor who supervised my thesis was awarded a prize. (restrictive — distinguishing among the professors I've had)
O Professor Soares, que me orientou a tese, foi galardoado com um prémio.
Professor Soares, who supervised my thesis, was awarded a prize. (non-restrictive — already identified by name)
Multiple relative clauses stacked
You can stack both types in a single sentence. Watch the commas carefully:
Os alunos que tiveram aulas com o Professor Silva, que se reformou em maio, guardam uma grande saudade dele.
The students who had classes with Professor Silva, who retired in May, miss him a lot.
Here, que tiveram aulas com o Professor Silva is restrictive (it picks out which alunos), while que se reformou em maio is non-restrictive (it adds a comment about the already-named Professor Silva). Two clauses, two different jobs, two different comma patterns.
O projeto em que estou a trabalhar, que começou no ano passado, envolve três países.
The project I'm working on, which started last year, involves three countries.
In this one, em que estou a trabalhar is restrictive (which project? the one I'm working on), and que começou no ano passado is non-restrictive (an additional comment).
Common Mistakes
❌ O livro, que comprei ontem, está na mesa.
Incorrect if you mean to identify which book — the commas turn it into a throwaway comment, implying the book was already identified.
✅ O livro que comprei ontem está na mesa.
The book I bought yesterday is on the table. (restrictive — no commas)
❌ O meu pai que é médico vai dar uma palestra.
Incorrect if you have only one father — the missing commas imply you are distinguishing among multiple fathers.
✅ O meu pai, que é médico, vai dar uma palestra.
My father, who is a doctor, is going to give a talk. (non-restrictive — only one father)
❌ A Ana que mora em Paris chegou ontem.
Sounds like you are distinguishing this Ana from other Anas — usually wrong with a proper name.
✅ A Ana, que mora em Paris, chegou ontem.
Ana, who lives in Paris, arrived yesterday. (non-restrictive — Ana is already identified)
❌ Os funcionários que chegaram atrasados, perderam o bónus.
Incorrect — you cannot have one comma only. Either both or neither.
✅ Os funcionários que chegaram atrasados perderam o bónus.
The employees who arrived late lost the bonus. (no commas — restrictive)
❌ Lisboa que é a capital de Portugal fica no estuário do Tejo.
Incorrect — Lisbon is already uniquely identified; the clause is non-restrictive and needs commas.
✅ Lisboa, que é a capital de Portugal, fica no estuário do Tejo.
Lisbon, which is the capital of Portugal, lies on the Tagus estuary.
Key Takeaways
- Restrictive clauses identify which — they are essential, and they take no commas.
- Non-restrictive clauses add extra information about something already identified — they are parenthetical, and they take commas on both sides.
- Proper names and unique referents almost always take non-restrictive clauses.
- Que works for both types; o qual is much more common in non-restrictive clauses and often used for disambiguation.
- In speech, non-restrictive clauses have lower pitch and pauses; restrictive clauses flow into the surrounding material.
- Comma placement is not decoration — it changes the meaning of the sentence.
Related Topics
- Relative Clauses OverviewA2 — How relative clauses work in European Portuguese — que, quem, o qual, cujo, onde, and the restrictive vs non-restrictive distinction.
- Relative Clauses with PrepositionsB1 — How to build relative clauses when the verb inside needs a preposition — em que, de que, com quem, a quem, sobre o qual.
- Relative Clauses with Cujo (Possessive)B2 — Building possessive relative clauses — the syntax, word order, and formal register of cujo-clauses.
- Relative Pronoun Que (The Most Common)A2 — The workhorse relative pronoun of Portuguese — used for people, things, and concepts, as subject or direct object of the relative clause
- Relative Pronoun O Qual / A Qual (Formal with Prepositions)B2 — The variable, formal relative pronoun that agrees in gender and number — used mainly after prepositions and to resolve ambiguity
- Relative Pronoun Quem (Referring to People)B1 — The relative pronoun used specifically for people — mostly after prepositions or as a free relative meaning 'whoever'