3 Easy Ways to Block Websites on Firefox in 2026

Cisdem AppCrypt

Block Sites on Firefox on PC

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There are all sorts of reasons for us to block websites on Firefox, especially you notice the websites are offensive or you need set up Firefox parental controls. Plus, when using Firefox on Mac in office, you might also intend to block special websites on Firefox to avoid being peeped, like Facebook, Twitter, LinkedIn, etc.

As far as I know, Firefox doesn’t provide a built-in function to block websites. So what will you do to fulfill the purpose? In this article, we offer three ways to you on how to block websites on Firefox.

How to block websites on Firefox using add-ons

Firefox contains a large number of add-ons that you are able to apply for blocking certain websites. To be precise, these add-ons actually are extensions which can be added to Firefox and perform their given functions. If you are interested in this kind of method, please read the steps below to learn how to block websites on Firefox using add-ons.

1. Open Firefox. Click the Extensions icon in the upper right corner. Then click the Disover extensions button.

2. Search for extensions that can block websites on Firefox in the top search bar. Here we will set Block Site by Ray as an example.

3. Click Add to Firefox to install this extension to your browser. Click Add in the pop-up window.

4. Go back to main interface and click Extensions. Click the Settings icon next to Block Site. Select Options.

5. Now you can add any website, such as facebook.com, in the box below Block a new hostname. Then click Add.

How to block websites on Firefox by editing the hosts file

The Hosts file is a system file that is mainly used to transfer domain names to IP address. It is small in your operating system, but it plays an important role on mapping hostsnames to stipulated IP address. Using Hosts file to block websites on Firefox is also simple, below are the steps on Mac.

1. Open Finder and navigate to Go > Go to Folder in menu bar. In the box, type /etc/hosts or /private/etc/hosts and hit Enter.

2. Find the Hosts file and drag it to desktop for edicting. Since the original file is locked.

3. Edit the Hosts file on desktop. If you want to block Facebook website on Firefox, you can write 127.0.0.1 www.facebook.com or 0.0.0.0 www.facebook.com.

4. Drag the desktop file back to the original location and replace the old Hosts file. Then your Facebook website will be blocked on Firefox.

How to block websites on Firefox on PC using Cisdem AppCrypt

Cisdem AppCrypt is a powerful and full-featured website blocker and app locker. It lets you block any websites or web pages on Windows and Mac with a password. You can also block inappropriate or distracting websites in bulk. In addition, the Schedule feature allows you to set time limits for certain websites, such as online games or social media, helping you stay focused while working.

Note: Website blocking on Firefox is currently not available for Mac.

Key features of the website blocker for Firefox:

• Clean interface and easy to use.
• Lets you block specific sites, categories of sites, or URLs containing specific word.
• Allows you to block websites or apps at specific times once a schedule is set.
• Offers two blocking options: block specific websites or allow only approved websites.
• If someone attempts to access blocked apps and enters the wrong password, the system will record the failed attempts.
• Runs in the background and use little CPU.

Steps to block a website on Firefox on Windows PC:

1. Download and install Cisdem AppCrypt on your PC.

Free Download Windows 10 or later

2. Launch the app. Set a password. Click Submit.

3. Click its icon on the taskbar. Click Open Main Window.

4. Enter the password to access the main window.

5. To block website on Firefox, go to the Web Block tab. Click the Install button next to Firefox. Follow the prompts to install the extension in your browser.

Tip: If you want to block sites on other browsers too, such as Edge, Chrome, install the extension to those browsers as well.

6. In the top URL field, enter the domain name of the site you want to block on Firefox. Click Add.

You can also add a keyword, which can block all URLs containing this keyword on Firefox.

Or, click the Import button. Select a category of sites to block, such as Games Sites, Social Sites.

Conclusion

Block sites on Firefox helps reduce distractions, and prevent access to harmful content online. This article introduces 3 easy ways to get the job done. If you are a Windows user and not tech-savvy, Cisdem AppCrypt is the best choice. This website blocker allows you to block sites across all major browsers on your PC. You can also set it to work exclusively on Firefox.