How to fix a WordPress child theme not working

What this problem looks like

Child themes live in their own folder but depend on a parent theme for most templates. WordPress reads the Template header in child style.css to locate that parent.

Linux hosting is case-sensitive. Template: MyTheme fails if the folder is named mytheme.

Minimum child theme files

A valid child needs style.css with headers and optionally functions.php. Other templates override parent files only when copied into the child folder.

css

/*
Theme Name: My Theme Child
Template: my-parent-theme
Version: 1.0.0
*/

Load parent styles correctly

php

add_action( 'wp_enqueue_scripts', function () {
    wp_enqueue_style(
        'parent-style',
        get_template_directory_uri() . '/style.css',
        array(),
        wp_get_theme( 'my-parent-theme' )->get( 'Version' )
    );
    wp_enqueue_style(
        'child-style',
        get_stylesheet_directory_uri() . '/style.css',
        array( 'parent-style' ),
        wp_get_theme()->get( 'Version' )
    );
} );

Symptoms and fixes

Broken parent theme is missing: install and activate parent first.
Unstyled layout: parent CSS not enqueued in functions.php.
White screen: syntax error in child functions.php. Check wp-content/debug.log.
Wrong templates loading: child file names must match parent template filenames.

Recover when the child whitescreens

Rename the child theme folder in wp-content/themes/ via File Manager, SFTP, or FTP to disable it. WordPress falls back to the parent if it was active underneath or to a default theme.

Fix functions.php locally, upload the corrected file, and reactivate.

Block themes and full site editing

FSE themes use theme.json and templates in the Site Editor. Child theme setup differs from classic themes. Follow the parent author FSE child documentation when available.

When to stop DIY and hire help

Child theme PHP errors are quick to fix with logs but scary on production. BugShield developers repair theme errors and restore layouts at a confirmed fixed price.

Questions answered

WordPress child theme not working FAQs

Answers about stylesheet headers, parent themes, asset loading, template overrides, caching, and safe customisation.

Does the child need every parent template copied?

No. WordPress falls back to parent templates for files not present in the child folder.

Can I rename the parent theme folder?

No. The child Template header must match the parent directory slug. Renaming the parent breaks the child.

Why are my child CSS changes ignored?

Caching plugins and CDNs serve old CSS. Purge cache and bump the Version in style.css.

Should I activate parent or child?

Always activate the child. Activating only the parent ignores child overrides.

What causes a WordPress child theme not to work?

Common causes are an incorrect Template header, missing parent theme, inactive child theme, stylesheet enqueue error, stale cache, outdated template override, or PHP error.

What should the Template value be in a child theme style.css?

It must exactly match the parent theme folder name, including case on case-sensitive servers. It is not the display name shown in wp-admin.

How should a WordPress child theme load its stylesheet?

Enqueue styles through functions.php using WordPress functions. Avoid relying only on @import, which is slower and can produce the wrong order.

Why are child theme changes hidden by cache?

Page, server, CDN, browser, and generated CSS caches may still serve the previous file. Purge each layer and confirm the requested stylesheet URL and version.

Can an outdated child theme template break after a parent update?

Yes. Compare the override with the current parent template and copy only the custom changes into an updated version.

When should a developer fix a WordPress child theme?

Get help when custom PHP fails, WooCommerce templates are outdated, or repairing inheritance could overwrite business-specific design and functionality.

Keep troubleshooting

Learn how to fix a WordPress child theme not working.