How do I create a Joomla child template?

Open System → Site Templates , open Cassiopeia (or another inheritable parent), click Create Child Template , name it, then close. Open the new template, add files, then assign its style under Site Template Styles .

What problem do Joomla child templates solve?

Edits inside Cassiopeia (or any parent) disappear when that template updates. Duplicating the whole template avoids the wipe but blocks future parent fixes. A child keeps only your files, so the parent can still update.

Why use a Joomla child template?

So Joomla can update the parent while your CSS, layout overrides, and extra positions stay in a separate folder. You also get more than one look from the same parent, and you can brand Atum the same way.

Which Joomla version do I need?

Joomla 4.1.0 or later , including Joomla 5 and 6. Joomla 3 and Joomla 4.0 have no Create Child Template button in core.

Why is the Create Child Template button missing?

You are below 4.1, or the template is not inheritable. Open templateDetails.xml and look for <inheritable>1</inheritable> .

Where do I put user.css?

In the child, New File → css folder → filename user → type .css . On disk: media/templates/site/your_child/css/user.css .

Is a child template the same as a template style?

No. Create the child under Templates. Assign it under Template Styles (default or Menu Assignment). You need both for the public site to change.

Do I have to copy index.php?

No. Most setups only need user.css and maybe one override. Copy index.php when you add positions or change page chrome. On Joomla 6, try Cassiopeia Extended’s colour and font tabs first.

Can I set up a child of the administrator template?

Yes. System → Administrator Templates → Atum → Create Child Template , then assign the admin style.

What if my commercial template has no child button?

It is probably not inheritable. Use the vendor’s custom CSS feature, ask them for a 4.1+ inheritable build, or switch to an inheritable parent. Do not only add <inheritable>1</inheritable> if CSS still lives under templates/ .

How do I make my own template support child templates?

On the parent : set <inheritable>1</inheritable> , move CSS, JS, and images into media/ with a <media destination="templates/site/yourtemplate"> block, stop building URLs with $this->template , then reinstall so the style row updates. After the Create Child Template button appears, create the child as usual.

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How to Set Up a Joomla Child Template

Stop editing Cassiopeia. A child template keeps your CSS and overrides when Joomla updates the parent. Setup for 4.1, 5, and 6, including how to make any template inheritable.

Abhilash Sahoo

Aug 22, 202617 min read

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Written by

Abhilash Sahoo

Abhilash Sahoo, with over 16 years of experience, is Founder & CEO of Infyways Solutions. He builds web platforms and eCommerce on Joomla, WordPress, Shopify, Magento, and OpenCart, plus modern stacks like Next.js, React, Node.js, and Python, with AI agents, automation, and headless CMS when products need to scale.

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How to Set Up a Joomla Child Template

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Abhilash Sahoo

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