Introduction
This article explains how to use Não acho que in Brazilian Portuguese together with the subjunctive mood. You will learn when to trigger the subjunctive, which verb forms to use, why native speakers sometimes prefer indicative, and useful example sentences for everyday conversation.
What does Não acho que mean?
Não acho que literally means I do not think that. It expresses doubt, negation of belief, or lack of certainty about a statement. In Portuguese grammar, this kind of negated opinion often calls for the subjunctive mood in the subordinate clause, because the speaker distances themselves from the factual status of what follows.
When to use the subjunctive after Não acho que
Use the subjunctive when the main clause expresses doubt, uncertainty, desire, emotion, or negation of belief. Não acho que is a negative expression of belief, so it normally triggers the subjunctive in the subordinate clause.
Examples of subordinate contexts that commonly use subjunctive after Não acho que:
– When you reject the truth of a statement or doubt that something will happen.
– When the action in the subordinate clause is not presented as a fact.
Common subjunctive tenses used
The most frequent subjunctive tenses after Não acho que are the present subjunctive and the past (imperfect) subjunctive. Choose present subjunctive for present/future uncertainty and imperfect subjunctive for hypothetical or counterfactual past situations.
Present subjunctive formation (regular verbs):
– falar: eu fale, você fale, nós falemos, eles falem
– comer: eu coma, você coma, nós comamos, eles comam
– partir: eu parta, você parta, nós partamos, eles partam
Imperfect subjunctive formation (regular verbs):
– falar: eu falasse, você falasse, nós falássemos, eles falassem
– comer: eu comesse, você comesse, nós comêssemos, eles comessem
– partir: eu partisse, você partisse, nós partíssemos, eles partissem
Examples with explanations
Below are practical examples showing how Não acho que behaves with the subjunctive in different contexts. Each example includes a translation and a short note about why the subjunctive is required.
Present/future uncertainty
Example 1:
Não acho que ele venha amanhã.
I do not think that he will come tomorrow.
Note: The speaker doubts a future event, so the present subjunctive venha is used to indicate uncertainty.
Example 2:
Não acho que isso funcione sem ajuda.
I don’t think that this will work without help.
Note: The action is not presented as fact; funcione uses the present subjunctive to show possibility or doubt.
Opinion about abilities or states
Example 3:
Não acho que ela saiba a resposta.
I don’t think she knows the answer.
Note: The main clause denies belief in a present state, so the present subjunctive saiba is correct.
Example 4:
Não acho que eles estejam prontos ainda.
I don’t think they are ready yet.
Note: This uses the present subjunctive estejam because readiness is uncertain from the speaker’s perspective.
Past situations and hypothetical meaning
Example 5:
Não acho que ele tivesse tempo para atender você naquela hora.
I don’t think he had time to meet you at that time.
Note: The imperfect subjunctive tivesse indicates a past situation about which the speaker doubts or speculates.
Example 6:
Não acho que ela soubesse do problema antes de tornar público.
I don’t think she knew about the problem before it became public.
Note: Soubesse shows that the speaker is not asserting knowledge as fact; it’s hypothetical or uncertain.
When speakers sometimes use the indicative instead
In informal spoken Brazilian Portuguese, you may hear the indicative after Não acho que, especially in negative sentences where the speaker really believes something is false and treats it as factual. This is a register and pragmatics issue rather than formal grammar.
Example (colloquial):
Não acho que ele vem hoje.
A native might use vem (indicative) instead of venha (subjunctive) when speaking casually and treating the event as unlikely but still stating it as a fact of their belief.
However, in formal writing and in careful speech, the subjunctive is preferred because the structure expresses doubt or negated belief.
Why the subjunctive fits here
The subjunctive flags the subordinate clause as non-factual or dependent on the speaker’s attitude. With negated verbs of opinion like Não acho que, the speaker creates distance from the truth of the clause, which is exactly the function of the subjunctive mood.
Structure and word order
Typical word order uses the main clause with Não acho que followed by the subordinate clause in subjunctive:
Subject + Não acho que + subordinate clause (verb in subjunctive)
Examples:
Eu não acho que isso seja necessário.
Ela não acha que nós devamos ir agora.
Note on contraction: Não acho que is not contracted. Do not combine it with que in any other special form. The que remains the subordinating conjunction that introduces the subjunctive clause.
Using negatives and adverbs
You can add adverbs and modal phrases that change emphasis without altering the need for subjunctive:
Não acho que isso seja verdade.
Não acho que isso seja verdade, sinceramente.
Não acho que ele vá aceitar, provavelmente.
Adverbs like provavelmente, talvez, and possivelmente can increase the sense of uncertainty but do not remove the subjunctive requirement after a negated opinion.
Common verbs similar to Não acho que
Many verbs and expressions behave similarly and require the subjunctive when negated or when expressing doubt:
– Não penso que
– Não creio que
– Duvido que
– Não tenho certeza de que (or Não tenho certeza se… + subjunctive)
Compare:
Não acredito que ele tenha dinheiro.
Duvido que ela possa vir.
Positive vs negative forms
When these verbs are positive, they usually take the indicative because the speaker is asserting belief.
Acho que ele vem amanhã. (indicative vem, assertive belief)
Não acho que ele venha amanhã. (subjunctive venha, doubt or negation)
Questions and polite negative opinions
You can use Não acho que in polite disagreement or softer negation. It is often heard in conversations where you want to avoid strong contradiction.
Example (polite):
Não acho que seja uma boa ideia mudar tudo agora.
I don’t think it’s a good idea to change everything now.
In Brazilian Portuguese this phrasing softens disagreement and invites discussion rather than confrontation.
Alternatives to express similar meanings
If you want variety or different levels of certainty, try these alternatives:
– Acho que não + indicative (used informally)
– Não acredito que + subjunctive (stronger disbelief)
– Duvido que + subjunctive (stronger doubt)
Example comparisons:
Não acho que ele venha. (I don’t think he’ll come — mild doubt, subjunctive preferred)
Acho que não vem. (I think he won’t come — informal, indicative)
Tips to practice and recognize usage
1. Listen to native speakers: pay attention in conversations and soap operas to how speakers use Não acho que and whether they choose subjunctive or indicative in different contexts.
2. Read formal texts and news articles: the subjunctive after negated opinion is more consistent there, which helps you internalize correct grammar.
3. Create your own sentences using present and imperfect subjunctive forms to describe uncertain present/future events and doubtful past events.
Common mistakes to avoid
– Using the indicative after formal negated opinion: in writing, prefer the subjunctive after Não acho que to be grammatically correct.
– Forgetting to match tense: choose present subjunctive for present/future uncertainty and imperfect subjunctive for past hypotheticals.
– Overusing indicative forms because they sound familiar in casual speech. Recognize register differences.
Cultural note
Brazilian Portuguese often favors indirectness and politeness in everyday speech. Using Não acho que with the subjunctive is not only grammatically correct but also culturally aligned with softer disagreement and respectful conversation. In many social contexts, people prefer less direct refusals or contradictions, and this structure helps achieve that tone.
Conclusion
Não acho que is a staple phrase for expressing doubt or negated belief in Brazilian Portuguese and normally requires the subjunctive in the subordinate clause. Use the present subjunctive for present or future uncertainty and the imperfect subjunctive for doubtful past situations. Remember that informal speech sometimes uses the indicative, but formal and written Portuguese favors the subjunctive. Listening, reading, and practicing with real sentences will help you master this useful structure.
