Acting as an expert witness

If you are summoned to the courthouse to provide an expert opinion concerning certain facts, objects or documents presented at a criminal trial, your opinion will be considered as testimony by the court.

As an expert witness, you are required to testify, or face the possibility of being charged with contempt of court. You could then be fined or imprisoned, or both. However, you do have certain rights.

Under the Statement of Principle regarding Witnesses, various measures will be taken to protect your rights and minimize the negative impacts of giving testimony.

As an expert witness, your role is to help the court gain a better understanding of the facts by providing expert knowledge about certain elements, for example by

  • estimating the value of a piece of jewellery, work or art or comic book;
  • explaining the physical or mental state of the accused;
  • examining the contents of a document.

For this purpose, you must answer the questions posed by the lawyers for the prosecution and defence.

At the Court of Québec, you may be a witness in a criminal trial

Any person asked to provide the court with an expert opinion.


To prepare for giving testimony, you must familiarize yourself with the object or document, for example, that you are being ask to asses. 

If you took notes during or after the event, you should re-read them too; to include them in your testimony, you must first forward them to the investigating officer.


To testify: 

  • go to the place specified in your summons at the date and time indicated;
  • inform the investigating officer or defence lawyer, depending on which side summoned you, that you have arrived;
  • go to the courtroom where the trial is to be held.

Postponement of testimony

For a serious reason, you can request the postponement of your testimony by contacting the court office or the party that summoned you.

Daily indemnity

Whether you testify or not, you can claim an indemnity for transportation, parking, meals and accommodation for every day you attend court.


You can claim the cost of public transportation for your trip to and from the courthouse.

If you travel by car, you can claim $0.43 per kilometre, plus the cost of parking.

Receipts may be required.


You can claim meal costs up to:

  • $10.40 for breakfast;
  • $14.30 for lunch;
  • $21.55 for dinner.

These amounts include tax and tips.

Receipts will be required.


You can request an allowance for accommodation if you decide to sleep at a hotel because of the distance between your home and the courthouse, and the fact that you need to appear on several consecutive days. The allowance ranges from $79 to $138 per night in a hotel.

You will be required to present receipts.

However, the amount of your allowance will always be calculated as if you had chosen the least costly option.

Indemnity for loss of time

You are generally entitled to an indemnity for the time spent at the courthouse, at the rate of:

  • $180 per day;
  • $90 for 5 hours presence or less.

You have many obligations, for example:

  • to comply with the summons you received;
  • to follow the judge’s instructions, such as waiting outside the courtroom until it is your turn to testify;
  • to testify and answer questions;
  • to tell the truth.

You also have rights, for example concerning:

  • the protection of your employment;
  • self-incrimination;
  • intimidation.

Protection of your employment

You are entitled to the protection of your employment. Your employer must allow you time off to testify, and cannot impose a penalty for that reason.

If your employer fails to respect your rights, you can file a complaint with the Commission des relations du travail or launch penal proceedings.


You are entitled to a degree of protection with regard to your testimony before the court. Anything you admit to in your testimony cannot be held against you in another case, except if you lie to the court or give contradictory testimony.


You are also protected against intimidation. If anyone attempts to influence your testimony or discourage you from testifying, for example by threatening you, you can report them to the police or a prosecutor and charges will be laid. 

Interpretation services

You can ask for an interpreter if:

  • you are hearing-impaired;
  • you are not fluent in the language used at the hearing.

Your duties as an expert witness end when you are released by the judge, generally once you have testified. Until then, you must remain at the court’s disposal.

In some cases, the judge may authorize you to leave before you have testified, for example if:

  • the accused has pleaded guilty;
  • the accused has waived the right to a preliminary inquiry;
  • the facts on which you are to testify are not contested.

The judge may also authorize you to leave because the case has been postponed. In this situation, the judge may:

  • tell you when you are to return to court;
  • tell you that you will be sent a new summons.
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