Firefox is the second most popular browser in the world after Chrome. It is one of the few browsers with its own web engine, so it has its own advantages unavailable in Chromium browsers. Mozilla, in developing this browser, focuses on the speed and user privacy protection. For example, Firefox has built-in tracking protection which can be customised to user preferences. There is also an HTTPS-only mode, cookies management, permissions control, and others.

But all these measures don’t protect against annoying and excessive advertising on websites. The Internet is full of recommendations and tips for dealing with ads in Firefox, each of them has its own characteristics.

Let's explore the most popular ways to block ads in Firefox and test their effectiveness in practice so that you can choose the best one for yourself. For each method, I will run 2 small tests to highlight the real blocking efficiency. The first test will be a randomly selected web page with embedded ads opening. For the second test, I will use the web service for checking ad blockers. Without using any ad blocking methods, we have a result of 36 points out of 100.

Well, let's move on.

Best Ad Blocker for Firefox Browser

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Method 1. Ad blocker in the browser

The first and most popular method is to use an ad-blocking add-on in your browser. Add-on – this is a small program which adds new or extends existing browser functionality. Large software vendors (such as Mozilla) have their own stores for add-ons by third-party developers.

All updates and themes for Firefox are available in the Firefox Browser Add-ons section on the official website. Also the most popular you can find and install directly from the built-in add-on manager. Let's use the built-in search and enter the word "ad block" in the search box.

For demonstrating this ads blocking method, I will use 3 ad blockers: Adblock Plus, AdGuard and uBlock. They are in the top 10 most popular ad blockers and have adapted versions for Windows, MacOS and Android. Let's start from Windows.

  1. Open Firefox and hold Control, Shift and “A” key together to open the Add-ons manager.
  2. Find the search bar at the top, type “adblock” there and press Enter. This list contains all ad blockers that are available for installation in Firefox. But if you are looking for a specific one, change your search query and enter, for example AdGuard.
  3. The process of add-ons installation in Firefox is very easy. You need to click "Add to Firefox" on the add-on page and confirm the permissions required for its work. After installation, don’t forget to enable it in private mode and check its settings in the just opened tab. For example, with AdGuard, you can additionally enable an anti-phishing module, auto-update filters, set up a whitelist, and much more.

Now let's do our tests. We load the first web page and see that banners have been removed, which is a good sign. Now let's run the second test and we get a blocking efficiency score 84 out of 100. Okay, now let’s move to the MacOS.

In MacOS, the installation process will be almost identical:

  1. Open Firefox and hold down Command and “A” to open the Add-ons Manager.
  2. Then adblocker name in the search box, let’s use the Adblock Plus in this case.
  3. Go to the add-on page, install it and give the required permissions to work. A new tab was opened too, but instead of settings it requested a donation. This is a voluntary fee, which wouldn’t affect the functionality of the add-on in any way, so do as you wish.

In any case, as Adblock Plus didn’t open its settings page, I additionally show you how to change the add-on settings in Firefox. To do this:

  1. Open the Add-ons Manager again and go to the Extensions tab.
  2. Find your add-on in the list and click on the 3 dots next to it.
  3. In the add-on that appears, select Settings and now you can customise Adblock Plus to suit your needs. As you can see, there are fewer options than in AdGuard, but despite this, almost 5 million users use it, according to their Firefox Add-Ons store.

And our tests. The first test is Passed because the banners are hidden. And the second test - gives an excellent result in 100 out of 100 blocking points.

As for Android, due to the nature of the platform, there are very few browsers that support the installation of add-ons. In addition, where this feature is available, only a small number of them are available for selection.

The undoubted advantage of Firefox is that its menu on different platforms looks more or less the same. Therefore, to manage add-ons in Firefox for Android, just like in desktop versions: open the browser, click on the three dots and select Add-ons.

To install an add-on, such as uBlock, click the plus next to its badge. Then, as usual, grant permissions and confirm working in private mode. To configure it, wait until the add-on appears in the “Enabled” list, click on its badge and select Settings.

Now let's test how ads blocking works in Firefox for Android. We opened the first website - there are no banners. Then, we open our second site and get 100 out of 100, which is pretty good.

So, our tests showed that browser extensions are one of the best ways to block ads in Firefox. There are hundreds of different ad blockers available in the official Firefox Add-ons Store. They are free and paid, with a customizable list of filters, additional security options, etc. Also, extensions from an official source can receive block lists regular updates while Firefox team regularly checks their safety.

Method 2. Internal browser tools

The next method is based on non-standard use of the built-in features of Firefox. As I said earlier, Mozilla's browser development is focused on user privacy. In particular, this is why Firefox has some exclusive features unavailable in its closest competitor - Chrome.

I will not describe in detail all Firefox features, as this is a topic for a separate large video. However, if you are interested, then write in the comments and I will prepare a separate review of all the features of the browser.

  1. Open your browser settings and go to the Privacy & Security section.
  2. Let's start with the feature at the end of the list, the HTTPS-only Mode. This feature enables using only https connections and disallows unencrypted http connections. We select the first work option to enable it in both private and normal modes. Now, the browser will automatically block connections via the legacy http protocol, which is still used by some ad providers.
  3. Next, we need to switch the “Do Not Track” feature to “Always” option. Firefox will send the signals to websites that you don't allow them to track your activity. Authoritative sites take into account such signals, so it may lead to full or partial tracking disabling, which is necessary for ad targeting. As result, this may also lead to disabling ads, as you will be irrelevant to the advertiser. But in addition to authoritative sites, there are thousands and millions of sites that ignore such signals and our next step will be for them.
  4. Scroll up a few more tabs and you'll see a description of Enhanced Tracking Protection, a key Firefox feature which you will use to block ads. You can read a brief description of this feature right here, when you activate it. I’d rather tell you how to use it if it “breaks” your favorite sites.

Set the switcher to “Strict” to complete the ad blocking setup. In this mode, Firefox will block cookies, which may break some sites, especially their authorization modules. So let's open any site and click on the shield icon next to the address bar.

If you notice that the site is unstable and wants to add it to the Enhanced Tracking Protection mode exclusion list, then click on this switcher. Now this site will work as usual, even with the "HTTPS-only" and "Do Not Track" features enabled. If the problems persist, try turning them off one by one.

You can manage the white list of sites on the same tab with your browser settings. Just click on "Manage Exceptions" and you will see a list of all excluded sites. Accordingly, to remove a site from this list, you need to use this button right here or open it again and change the switcher state again.

As the first test shows, this method can successfully block regular ads on websites. But the second test showed that although it raised the effectiveness of blocking only in 68 points, this does not guarantee complete protection against static graphic ads.

The main advantage of this method is that the user doesn’t need to install any additional software or add-ons. All the necessary functions are already available out of the box and can be easily configured. In addition to blocking ads, these features also increase your privacy on the Internet by blocking various trackers. The disadvantage of this method is that you must exclude sites from ads blocking if it breaks their functionality and visibility.

Method 3. Adblock software on the device

The next way to block ads in Firefox is to install adblock software on your device. Such programs take under control all your traffic and remove requests to resources with ads sources. Most often this process is based on a list of filters, like in simple browser add-ons. But in this case, ads will be removed in all browsers and software with Internet access installed in your system.

For example, here's AdGuard. Since I used the same ad blocker on all three platforms, I conduct tests only on Windows platform. The basic test was successful, both the side and top banners were hidden, while the second test was rather unusual. The first launch of this web page showed such poor results that I began to think that the effectiveness of AdGuard is just a marketing trick.

But after a few restarts of the test, the blocking efficiency grew and in the end I got results in the range of 70-80 points, which is already a pretty good indicator. Then, for the experiment, I also connected the AdGuard browser extension and this gave me a stable blocking result of 92 out of 100.

Based on this, two conclusions can be drawn.

  1. If the ad blocker has a version for the browser and for the device, then it is better to use them together to achieve the best result.
  2. Ad blocker vendors can use learning models to detect unknown ad blocks. Therefore, if you come across an ad that your ad blocker did not block, then block it manually and soon this ad provider will be automatically blocked for you and other users.

Anyway, this is the most radical method to block ads in Firefox, as it affects all device traffic, not the browser only. However, its effectiveness will be almost the same as with using a browser extension, but all Internet connections will be filtered. At the same time, for users with strict security policies this may be a minus, as ad blocker will also monitor traffic with limited access. A compromise in this situation can be in using ad blockers with the ability to set filtering rules only for certain programs.

Method 4. Ads blocking with DNS

A less known method to block ads in Firefox is by changing the default DNS service. This is a global Internet service that matches the literal addresses of sites (for example, Youtube.com) with their IPs to route traffic between users. And if this service doesn’t correctly match the addresses of the websites of advertising providers, then the advertising content on the web pages wouldn’t be downloaded.

The most well-known provider of such a solution is AdGuard. They have a publicly accessible DNS server with basic ad filters enabled. And now I'll show you how to install it in Firefox:

  1. Open Firefox and type in the address bar: "about:config".
  2. Click the “I accept risk” button to go to the specific browser settings.
  3. There will be a search bar at the top of the page. Use it to find the “network.trr.bootstrapAddress” parameter. Select the variable type String and enter 94.140.14.14. Don't forget to save your changes by clicking on this button on the right.
  4. Then find the network.trr.mode parameter and set it to 2.
  5. Finally, set the network.trr.uri parameter to the special URL "https://dns.adguad.com/dns-query".

A small advice - AdGuard also has a family DNS server where, in addition to advertising, there are also filter lists against phishing and adult sites. To connect to such a server use the 94.140.14.15 IP in 3 steps of this manual.

This ad blocking method is effective against known ad providers, as we can see on the first test web page. But the counter on the second one shows only 76 out of 100 because DNS blocking doesn't prevent various dynamic scripts from running on the page.

So, DNS ad blocking is a non-standard with a middle effectiveness solution. And according to the need of changing the key parameters of the browser, it is better to use it only as a “last hope solution”, in cases when the previous three are not available for some reason.