How to Set Up WordPress Multisite (2026 Guide)

How to Set Up WordPress Multisite

WordPress Multisite lets you run multiple websites from a single WordPress installation. It's useful for organizations managing many related sites, universities, or agencies hosting client sites.

When to Use Multisite

• Managing 5+ sites that share themes/plugins
• University departments or school districts
• Franchise businesses with location-specific sites
• Development agencies managing client microsites

When NOT to use it: If sites are unrelated, need different plugins, or require independent scaling. In those cases, separate WordPress installations on SiteICO give you better isolation and flexibility.

Step 1: Enable Multisite

Add this line to wp-config.php above the “stop editing” comment:

define('WP_ALLOW_MULTISITE', true);

Then go to Tools → Network Setup to configure your network as subdomain-based or subdirectory-based.

Step 2: Choose Subdomain vs Subdirectory

• Subdomain (site1.example.com): Better for distinct brands, requires wildcard DNS
• Subdirectory (example.com/site1): Simpler setup, shares the main domain's SEO authority

Step 3: Configure the Network

WordPress will display code snippets to add to wp-config.php and .htaccess. Add them exactly as shown. After completing this step, you'll see a new My Sites menu in the admin bar.

Step 4: Manage Themes and Plugins

As the network admin (Super Admin), you control which themes and plugins are available network-wide. Network-activate plugins to enable them on all sites, or allow individual site admins to activate them per-site.

Step 5: Add Sites to the Network

Go to My Sites → Network Admin → Sites → Add New. Set the site address, title, and admin email. The new site inherits the network's active theme and can be customized independently.

Multisite Limitations

• All sites share one database (performance ceiling with many sites)
• A plugin conflict affects the entire network
• Individual site admins can't install plugins
• Some plugins don't support Multisite

Alternative: Multiple Separate Sites

For complete isolation and independent scaling, run separate WordPress installations. SiteICO's management dashboard lets you control multiple sites from one interface without the limitations of Multisite, and each site gets its own container, database, and resources.