The WordPress ecosystem has changed significantly with the transition from classic themes to modern block themes. Sidebars, once defined in functions.php, are now fully block-based and visually editable inside the Site Editor. Widgets still exist—but in a very different form. Many website owners and developers are unsure how these components work today, especially when migrating older sites to new block-based layouts.
At Wisegigs.eu, we help teams modernize their WordPress setups by restructuring outdated widget areas into flexible, scalable block templates. This guide breaks down how widgets and sidebars work in block themes, where they live inside the WordPress editor, and how to use them to build more consistent layouts.
1. What Changed? Widgets in Classic Themes vs. Block Themes
Traditional WordPress themes used PHP-registered widget areas called sidebars. These were fixed “zones” where users could drop widgets like menus, search bars, and text content. Changing layout required editing theme files or using a page builder.
Block themes introduced a new approach:
Sidebars are now block templates, and widgets are simply blocks.
In classic themes:
Widget areas are registered in code
Appearance → Widgets
Sidebars follow a fixed layout
In block themes:
The widget screen still exists but is rarely used
Block patterns, template parts, and the Site Editor replace widget areas
Layout is more flexible, visual, and mobile-friendly
This shift reflects the broader move toward the WordPress block editor. WordPress.org explains how block themes aim to unify content and design under one editing experience:
WordPress Developer Blog — Intro to Block Themes: https://developer.wordpress.org/themes/block-themes/
2. What Are Sidebars in Block Themes?
In block themes, a sidebar is no longer a technical “widget area.” Instead, it is simply a template part—a reusable block layout inserted into multiple templates.
A sidebar may include:
Navigation menus
Recent posts
Search blocks
Categories
Promotional banners or CTAs
Custom block patterns
Because sidebars are built with blocks, you can fully customize:
Their width
Their position
Their visibility on devices
Their content layout
The flexibility eliminates many of the limitations of classic widget sidebars.
3. Where to Find Sidebars & Widget Areas in Block Themes
Block themes use the Site Editor instead of the old Widgets screen.
To edit your sidebar:
Go to Appearance → Editor
Open Template Parts
Select Sidebar, Blog Sidebar, or the equivalent
Edit it visually using blocks
You can reposition or replace the sidebar within templates such as:
Single Post
Page
Archive
Category
Blog Index
For reference, WordPress.org provides guidance on how template parts work across theme files:
Theme Template Parts Overview: https://developer.wordpress.org/themes/block-themes/template-parts/
4. Common Blocks Used as “Widgets” Today
Blocks have replaced nearly all traditional widgets. Many familiar tools still exist—just in block form.
Useful sidebar blocks include:
Search
Latest Posts
Categories List
Tag Cloud
Navigation
Social Icons
Custom HTML
Image or Banner
Buttons for CTAs
Developers can also create custom blocks with ACF or custom JavaScript.
5. Best Practices for Modern WordPress Sidebars
1. Keep the Sidebar Lightweight
Avoid adding too many visual or script-heavy blocks. Overloaded sidebars slow down mobile users.
2. Maintain Visual Consistency Across Templates
A sidebar should feel like part of the design system. Using a template part ensures consistency.
3. Prioritize Mobile Experience
Most modern designs hide or collapse sidebars on mobile.
Block themes allow conditional display settings for each block.
4. Avoid Widgets That Duplicate Functionality
Many plugin widgets (old-style) are obsolete. Use block equivalents instead.
5. Reuse Patterns for Faster Editing
If the same sidebar components appear on multiple page types, convert them to block patterns.
6. If Migrating From a Classic Theme, Expect Layout Differences
Migration requires restructuring, not simply copying “widgets.”
5. Best Practices for Modern WordPress Sidebars
1. Keep the Sidebar Lightweight
Avoid adding too many visual or script-heavy blocks. Overloaded sidebars slow down mobile users.
2. Maintain Visual Consistency Across Templates
A sidebar should feel like part of the design system. Using a template part ensures consistency.
3. Prioritize Mobile Experience
Most modern designs hide or collapse sidebars on mobile.
Block themes allow conditional display settings for each block.
4. Avoid Widgets That Duplicate Functionality
Many plugin widgets (old-style) are obsolete. Use block equivalents instead.
5. Reuse Patterns for Faster Editing
If the same sidebar components appear on multiple page types, convert them to block patterns.
6. If Migrating From a Classic Theme, Expect Layout Differences
Migration requires restructuring, not simply copying “widgets.”
7. Common Sidebar Layouts Used by Wisegigs Clients
At Wisegigs.eu, here’s what we implement most often:
Blog Sidebar Layout
Search
Latest Posts
Categories
Promotional CTA
Newsletter form (CRM-integrated)
Service Page Sidebar
Navigation menu
“Related Services” block
Downloadable PDF CTA
Trust badges / client logos
E-commerce Sidebar (WooCommerce)
Filters
Product categories
Promotions banner
Recently viewed items
Block themes provide the flexibility needed to maintain clean UX while supporting marketing goals.
Conclusion
Sidebars and widgets in modern WordPress have evolved into a flexible block-based system that provides greater control, cleaner design, and easier maintenance. Whether you’re building a lightweight blog or a full-scale business website, the block editor makes layout customization far more intuitive.
To get the best results:
Understand the difference between classic and block-based sidebars
Keep layouts streamlined and consistent
Use blocks instead of legacy widgets
Build reusable patterns
Ensure mobile responsiveness
With the right approach, sidebars become powerful tools for navigation, conversions, and user experience.
Need help modernizing your WordPress site?
Contact us today