You’ve been told you need to provide an affidavit for your court case. But what exactly is it, and why is it so important?
If you are involved in a legal dispute – whether its a family law matter, a contested will, or a commercial dispute – you have likely heard the word “affidavit.”
It sounds intimidating and technical. For many people, being asked to prepare one is the moment their legal matter suddenly feels very real.
Here is a straightforward guide to what an affidavit is, why courts use them, and how to get yours right.
The simple definition
An affidavit is your evidence in writing.
Instead of standing in a witness box in a courtroom and telling your story out loud to a judge, you write it down beforehand in a specific legal format.
But it isn’t just a letter. It is a formal legal document that you sign under oath or affirmation.
Why do courts use affidavits?
Courts use affidavits for efficiency.
If every single fact had to be told verbally in court cases would take months longer than they already do. Affidavits allow the Judge and the other party to read your evidence before the hearing starts. This saves court time and focusses the arguments on the key issues.
What goes into an affidavit?
Writing an affidavit is very different from writing an email. There are strict rules of evidence that dictate what can and cannot be included.
The most critical rule is an affidavit must contain facts, not opinions.
The Judge doesn’t want to know what you think happened or how you feel about the other person. They want to know what you actually saw, heard, or did.
The “first-hand” rule
Generally, you can only include things you know first-hand.
- BAD: “My ex-husband is a very aggressive person.” (This is an opinion/conclusion.);
- GOOD: “On Tuesday 23 December 2025 at 5pm the Respondent stood in my doorway. He was shouting and punched the wall.” (These are facts that let the Judge decide if he was aggressive.);
- BAD: “My neighbour told me that she saw him steal the car.” (This is hearsay – evidence based on what someone else said);
- GOOD: “I looked out the window and saw him drive away in the white Toyota Corolla.” (This is what you saw.)
Telling the truth
Because an affidavit is sworn evidence it carries significant legal weight.
Before you sign the final document you must take an “oath” (swearing on a religious text like the Bible) or make an “affirmation” (a non-religious solemn promise) before an authorised witness.
By doing this, you are subjecting yourself to the laws regarding perjury. Under NSW law intentionally providing false or misleading information in an affidavit is a criminal offence which can carry significant penalties, including jail time.
Additionally, if a Judge decides you have lied in your affidavit that will seriously damage your case.
Why you need a lawyers help
It is tempting to think “I know my story best, I’ll just write it myself.”
While you do know the facts best, lawyers know the rules of evidence best. If you file a DIY affidavit filled with opinions, hearsay, and irrelevant emotional outbursts, the other party’s lawyer will object to it.
The Judge may then order that large sections of your affidavit be struck out and you may be left with very little evidence before the court.
A good lawyer ensures your voice is heard in a way the court can actually accept.
Next steps
An affidavit is often the foundation of your entire legal case. It needs to be precise, truthful, and strategically drafted. Don’t try to navigate the rules of evidence alone. Schedule a consultation with us today to ensure your story is told correctly.
