The fastest way to block a website in Firefox

Firefox does not have a built-in website blocker in its main settings, but you can block sites in three ways: using parental controls if you manage a child's account, installing a free extension, or manually blocking a site through your browser's developer tools. The easiest method for most people is installing an extension like uBlock Origin or Freedom, which take about two minutes to set up and let you block any site with one click.

If you want to block a site right now without installing anything, you can also add it to Firefox's restricted sites list through the address bar — though this method is less reliable and only works in certain situations. For parents managing a child's Firefox account, Firefox has built-in parental controls that can block entire categories of sites or specific URLs.

Key Takeaways

  • Extensions like uBlock Origin and Freedom are the most straightforward way to block websites; both are free and let you block a site by right-clicking on it.
  • Firefox's parental controls can block specific websites or site categories if you are managing a child's account, but they do not work on your own adult account.
  • You can manually block a site through Firefox's address bar by typing the domain and using the browser's site information panel, though this method is less reliable than extensions.
  • Blocked sites will not load when you try to visit them, but the block only applies to your Firefox profile — other browsers and other user accounts are not affected.

Using an extension to block websites

Installing an extension is the most common way to block websites in Firefox. Open Firefox and go to the Add-ons page by clicking the menu button (three horizontal lines) in the top right, then select Add-ons and themes. Search for an extension like uBlock Origin, Freedom, or LeechBlock NG. Click Add to Firefox, then confirm by clicking Add in the popup that appears.

Once installed, most extensions add a button to your toolbar. To block a website, right-click anywhere on the page and look for an option like "Block this site" or "Add to blocklist" — the exact wording depends on which extension you chose. Some extensions, like Freedom, also let you set schedules so sites are only blocked during certain hours. You can manage your blocked list by clicking the extension's icon and selecting settings or options.

Different extensions have different features. uBlock Origin is lightweight and blocks ads as well as sites you choose. Freedom includes scheduling and works across multiple browsers. LeechBlock NG is designed specifically for blocking distracting sites and lets you set time limits. All three are free and do not require an account.

Blocking websites through Firefox parental controls

If you are setting up Firefox for a child, you can use Firefox's parental controls to block websites without installing an extension. First, create a separate Firefox user account for the child by clicking the menu button, selecting Settings, then Sync, and choosing Create a new account. Once the child's account is set up, sign into their Firefox profile.

In the child's profile, go to Settings, then Privacy & Security, and scroll down to Parental Controls. Check the box next to Enable Parental Controls. You can then block specific websites by entering their web addresses, or block entire categories like adult content, gambling, or violence. The child will see a blocked page if they try to visit a restricted site.

Parental controls only work on the child's Firefox profile — they do not affect your own account or other browsers on the computer. If the child uses a different browser like Chrome or Safari, you will need to set up blocking there separately.

Manually blocking a site through Firefox settings

If you do not want to install an extension, you can block a website by adding it to Firefox's restricted sites list. Navigate to the website you want to block, then click the lock icon or information icon next to the web address in the address bar. A panel will open showing the site's permissions. Look for an option to block or restrict the site — the exact wording varies depending on your Firefox version.

This method is less reliable than using an extension because it only prevents certain types of content from loading, not the entire site. It works best for blocking tracking scripts or ads from specific domains rather than blocking the main website itself. For a more complete block, an extension is the better choice.

What happens when you block a website

When you block a website in Firefox, attempting to visit it will show an error page or a blocked message, depending on which blocking method you used. If you used an extension, you will typically see a page that says the site is blocked, with an option to unblock it temporarily if the extension allows. If you used parental controls, the child will see a message explaining that the site is restricted.

The blocked site will not load any content, and you will not be able to access it by typing the address directly, using a search engine, or clicking a link. However, the block only applies to your Firefox profile — other people using the same computer with different Firefox accounts will not see the block, and the site will load normally in other browsers like Chrome or Safari.

Unblocking a website you blocked by mistake

If you blocked a website and want to unblock it, the process depends on which method you used. With an extension, click the extension's icon in the toolbar and look for your blocklist or blocked sites. Find the site you want to unblock and remove it from the list. Most extensions let you do this in one click.

If you used parental controls, sign into the child's Firefox profile, go to Settings > Privacy & Security > Parental Controls, and remove the site from the blocked list. If you manually blocked a site through the address bar, navigate back to it and click the information icon again to change the permission back to allow.

Frequently Asked Questions

Can someone bypass a website block I set up in Firefox?

If you are using parental controls on a child's account, they cannot bypass the block without your password. If you are using an extension on your own account, someone with access to your computer could disable the extension or unblock the site themselves. For stronger protection on a shared computer, consider using parental controls instead.

Will blocking a website in Firefox block it on my phone too?

No. Blocks only apply to the Firefox profile where you set them up. If you use Firefox on your phone, you will need to install the same extension or set up parental controls separately on the mobile version. Firefox on Android and iOS support extensions, though the selection is smaller than on desktop.

What is the difference between blocking a site and clearing my history?

Blocking prevents a site from loading when you try to visit it. Clearing your history removes the record that you visited a site in the past, but does not prevent you from visiting it again. They serve different purposes — blocking is for preventing access, and clearing history is for privacy.

Can I block a website for only part of the day?

Some extensions like Freedom include scheduling features that let you block sites during specific hours. Most other extensions block a site all the time. If scheduling is important to you, check the extension's description before installing to see if it offers that feature.

Does blocking a website use more of my internet or slow down Firefox?

No. Blocking a website actually saves bandwidth because the blocked site never loads. Extensions that block sites use very little memory or processing power, especially lightweight ones like uBlock Origin. You should not notice any slowdown in Firefox's performance.