Defamation law protects a person's reputation from harm caused by publication to a third person. A Facebook group post or comment is published to the group's members. This page covers defamation in Facebook groups, not social media generally. For social media generally, see Facebook defamation more generally.
Is a post in a private Facebook group defamation?
Yes. A private or closed Facebook group is still a publication to every member who can see it. The post need not be visible to the public. What matters is that a third person, not just the person defamed and the poster, could read it. A small group of your local customers may cause more harm than a large general group. If a member takes a screenshot and sends it outside the group, that person makes a new publication. That sharing is separate from your own evidence preservation. Keep your own screenshots of the post. The law does not require the group to be public.
Serious harm under section 10A of the Victorian Defamation Act is an element in every state and territory except Western Australia. In the NT the serious harm element has applied since 11 August 2025. The judge decides whether the post caused or is likely to cause serious harm to your reputation. In a private group, group size and whether members know you are practical evidence that may be relevant to harm. A post in a closed school parents group can be very damaging. The same words in an unrelated private group may not be. Gather the member list if visible, or at least the member count.
How to handle defamation in a Facebook group?
Your first step is to save evidence. Then report the post to Facebook. Then send a written complaint to the group admin. In most Australian jurisdictions, this starts a seven day window for the admin. You should also send a concerns notice to the poster. That notice must identify the post, set out the imputations, and describe the serious harm. See how to send a concerns notice. Before you file in Victoria, the concerns notice must be given and the applicable waiting period must expire. Most Australian states also require a notice, though Western Australia does not.
If the poster is anonymous, you may need preliminary discovery. Court rules let you ask the court for an order to identify the person or find an address. The court will consider privacy and safety factors. This is not automatic. See finding out who is behind an anonymous post. Watch the one year limit for defamation in Victoria. Serving a concerns notice in the last 56 days can extend the limitation period. For full details, see defamation time limits.
Can a Facebook group admin be sued for defamation?
Yes. A group admin can be a publisher of members' posts and should assume that risk. In Voller, the High Court decided that media companies with public Facebook pages were publishers of third party comments. That decision concerned a public page and decided publication only. It did not decide the position of a Facebook group admin or any defence. Victoria and several other states now have a defence for digital intermediaries. Under section 31A of the Defamation Act 2005, the admin must prove the elements. The defence applies only if the cause of action accrued after the commencement date. In Victoria that date is 11 September 2024. Older posts are governed by the previous law.
This defence applies only if the admin did not create the content. An admin who writes, edits, or endorses a defamatory post is not a digital intermediary. Simple moderation does not lose the defence. Removing spam or rule breaking posts is fine. Malice in establishing or providing the service defeats the defence. The admin also loses the defence by failing to have a complaints mechanism at the time of the post. Failure to take reasonable access prevention steps after a written complaint also defeats it. Publishing a clear complaints contact, such as an email or direct message address, is essential. Read more about new protections for page and group admins.
Not every state has this defence. Western Australia has no section 31A. South Australia has no section 31A either, though it has court orders against non party intermediaries. In those states, admins rely on older defences such as innocent dissemination. If you run a group and receive a complaint, seek advice promptly.
Are Facebook group admins liable for comments?
An admin can be liable if a member posts a defamatory comment and the admin does not use the statutory defence. The law looks at whether the admin provided the forum. Under the defence, the admin needs an accessible complaints mechanism at the time of the post. If a member sends a written complaint, the admin may need to take reasonable access prevention steps before the complaint or within seven days after it. This is a condition of the defence, not a legal duty. Asking the poster to remove it may also count. A concerns notice that includes the required information can serve as a complaint.
If no complaint is made, the admin only needs to show they had a complaints mechanism. The defence is not available for an admin who edited the comment. If you are an admin, avoid editing members' posts to change their meaning. Remove or hide the whole post instead. If you receive a concerns notice, the 28 day offer to make amends period applies. You can offer to take the post down. For more on defending a claim, see defending a defamation claim.
After judgment or an injunction, a court can order a non-party digital intermediary, such as an admin or Facebook, to take access prevention steps. Under Victorian law, section 39A permits this even when the intermediary is not liable. This power exists in every state and territory except Western Australia. The intermediary must be heard first, except for urgent temporary orders.
