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Contesting a Tax Assessment in Portugal

Researched and written with AI tools from official sources. How we make our guides

How to challenge a tax bill you think is wrong: the free 120-day complaint, the appeal, the tax court, tax arbitration, and stopping collection meanwhile.

The Portugal Brief 8 min read

Contesting a Tax Assessment in Portugal

Last verified: October 2026.

Who this is for

  • You received a tax bill or assessment from Finanças that you think is wrong.
  • It is for income tax (IRS), property tax (IMI), transfer tax (IMT), road tax, or another tax.
  • You live in Portugal or abroad, and you want to know your options and deadlines.

Not for you if: you made a mistake on your own income tax return and want to fix it. File a replacement return instead, as explained in Filing Your Annual Income Tax Return (IRS) in Portugal.

If you think a tax assessment is wrong, you can challenge it. The usual first step is a formal complaint to the tax office (reclamação graciosa). It is free, you do not need a lawyer, and you file it online on the Portal das Finanças. You have 120 days, usually counted from the end of the payment period on the bill.

If the complaint fails, you can appeal within the tax office, go to the tax court, or use tax arbitration. Challenging a bill does not stop collection on its own. To pause it, you usually need a guarantee or a waiver.

Your options at a glance

RouteDeadlineCostLawyer
Formal complaint (reclamação graciosa)120 daysFreeNo
Appeal up the chain (recurso hierárquico)30 days from the complaint decisionFreeNo
Tax court (impugnação judicial)3 monthsCourt feeMay be compulsory
Tax arbitration at CAAD90 daysArbitration feeCheck before filing

The court and arbitration deadlines run from the same starting points as the complaint, or from a decision on your complaint or appeal.

Step 1: check the deadline on the notice

Most deadlines run from a date linked to the notice (notificação). For a tax bill, the usual starting point is the last day of the voluntary payment period printed on it. For other decisions, it is the date you were notified.

Note that date as soon as the letter or portal message arrives. A missed deadline usually closes that route, however good your case.

If a new document or fact appears later that you could not have used in time, the 120 days run from when you could get it or learn of it.

Step 2: file a formal complaint (reclamação graciosa)

This asks the tax office to cancel or correct its own decision, in full or in part. You can raise any illegality, such as a wrong amount, a wrong value, a missing reason, or a missed step.

  1. Gather your evidence. The complaint relies on documents and on the tax office's own records, so attach everything that supports your case.
  2. Log in to the Portal das Finanças and use the option to submit a reclamação graciosa (Apresentar reclamação graciosa).
  3. Explain what is wrong and what you want changed. Keep it clear and factual.
  4. Submit and keep the proof. You can also file in writing at a tax office.

How long it takes. The tax office should decide within four months. If it does not, the law treats the silence as a refusal (indeferimento tácito). That lets you move to the next step without waiting.

Cost. The complaint is free. But if a complaint has no reasonable grounds at all, the tax office can add a charge of up to 5% of the tax in question.

You cannot file a complaint on the same grounds as a court challenge you have already filed.

Step 3: appeal up the chain (recurso hierárquico)

If your complaint is refused in full or in part, you can appeal to the most senior official above the person who decided.

  • Deadline: 30 days from the notice of the complaint decision.
  • Where: online on the Portal das Finanças (Apresentar recurso hierárquico). It is filed with the official who decided and passed up the chain.
  • Decision time: at most 60 days.
  • Cost: free.

This step is optional. You can go straight from a refused complaint to the tax court or to arbitration.

Step 4, option A: the tax court (impugnação judicial)

The tax court (tribunal tributário) can review any illegality in the assessment.

  • Deadline: three months. It runs from the end of the payment period, from the notice of the decision, or from the date a tacit refusal arises.
  • Where: you file at the competent tax court, or at the local tax office, which sends it on.
  • Cost: a court fee (taxa de justiça), based on the value of the case.
  • Lawyer: the tax office says a lawyer may be compulsory in court. Check before you file.
  • Speed: courts can take a long time. There is no official average time published.

If the ground is that the act is null, you can challenge it at any time.

Step 4, option B: tax arbitration at CAAD

Tax arbitration is an alternative to the tax court. Cases are heard at CAAD, the administrative arbitration centre. The tax office has agreed to accept arbitration for disputes up to €10 million, with some exceptions, such as customs duties on imports.

  • Deadline: 90 days, from the same starting points as the court route, or from the decision on an appeal.
  • How: you send an electronic request to CAAD's president.
  • Arbitrators: one arbitrator for smaller cases if you do not choose one; three for larger cases, or if you choose your own.
  • Speed: the decision is due within six months of the start. It can be extended by two months at a time, up to six months more.
  • Cost: an arbitration fee set by CAAD's cost rules, based on the value. If you do not choose an arbitrator, the decision says who pays the costs.
  • Appeals: limited. You can appeal to the Constitutional Court on constitutional points, or to the Supreme Administrative Court if the decision conflicts with another ruling on the same point of law.

You can use both court and arbitration on the same act only if the facts and grounds are different.

Stopping collection while you contest

A challenge does not stop Finanças collecting the tax on its own. After the payment period ends, unpaid tax can go to tax enforcement (execução fiscal).

Small debts. If you are an individual and the debt is under €5,000, enforcement pauses for up to 120 days after the payment period, without a guarantee, until you file your challenge. The pause ends 15 days after you file, unless you give a guarantee or get a waiver.

Giving a guarantee. To pause enforcement, you can give a suitable guarantee (garantia idónea). This can be a bank guarantee, a deposit (caução), or surety insurance (seguro-caução). The tax office may also accept a pledge or a mortgage. The guarantee covers the debt, interest, and costs, plus 25%.

Asking for a waiver. You can ask to be excused from the guarantee if giving it would cause you irreparable harm, or if you clearly lack the means to pay. Ask within 15 days of filing your challenge. The tax office should decide within 10 days. A waiver lasts one year.

If you give a bank guarantee and win, you can claim compensation for its cost. Normally it must have been in place for more than three years. That time limit does not apply if the tax office made the error.

If you win

The tax office must repay what you paid that was not due. If the complaint or court finds the tax office made the error, you also get compensatory interest (juros indemnizatórios) on the amount.

You also get interest if the tax office misses the legal deadline to repay, or takes more than a year to decide a review you asked for, unless the delay was not its fault.

If you missed the deadline: asking for a review

If the 120 days have passed, you may still ask the tax office to review its decision (revisão oficiosa). It can correct an error that was its own fault within four years of the assessment, or at any time if the tax has not been paid. Your request pauses that time limit.

A duplicate charge for the same tax can be reviewed within four years, whatever the reason. In cases of serious and obvious injustice, the head of the tax office can exceptionally allow a review within three years, if the error was not due to your negligence.

Getting help

You can file a complaint and an appeal yourself. For court or arbitration, or for a large bill, consider a lawyer or a certified accountant. If you cannot afford one, you may qualify for legal aid (apoio judiciário) from Social Security.

If your bill is for property tax, see Paying IMI Property Tax in Portugal. For an overview of each tax, see How Taxes Work in Portugal. If your dispute is with a person or a company, not the tax office, see Resolving a Dispute through the Julgados de Paz.

This guide is general information, not legal or tax advice. Rules change; check the official source, or ask a lawyer or a certified accountant (contabilista certificado), before you act.

Sources

This guide is written from official sources and, where relevant, organisations' own websites.

Last verified October 2026. Rules and fees change; check the official source before acting.

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