Official project (gorhill/uBlock)
Before You Start
Use an up-to-date Firefox on Windows, macOS, Linux, or Android. The current uBlock Origin release requires Firefox 115 or later; a supported, updated browser is recommended. This guide installs full uBlock Origin, which includes dynamic filtering and the full filter engine.
What you need: Firefox installed, 2 minutes, and access to Mozilla’s add-ons site.
What you’re installing: the full uBlock Origin extension, with dynamic filtering and the full filter engine available.
Install uBlock Origin in 3 Steps
No account is required. The cleanest path is to install directly from Mozilla Add-ons.
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Open the Firefox Add-ons page
Open the official uBlock Origin listing on addons.mozilla.org in Firefox. Confirm the publisher is Raymond Hill. If it offers to download Firefox, reopen the link in Firefox rather than your other browser.
Mozilla Add-ons, September 22, 2026. This view is from another browser; open the listing in Firefox to install. If uBO is already installed, the button shows Remove. -
Click “Add to Firefox” and approve permissions
Firefox will show a permission prompt. The “read and modify data on websites” permission is what allows the blocker to inspect requests, hide ad elements, and stop trackers before they load.
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Verify it’s working
After install, look for the uBlock Origin icon in the toolbar. If you do not see it, open the extensions button and pin it. Then load a page that normally shows ads and check whether the blocked-request counter starts climbing.
Install uBlock Origin on Firefox for Android
The full extension also works on Firefox for Android. Install it separately on your phone; a desktop installation does not add it to your mobile browser.
- Install or update Firefox for Android, then open its three-dot menu.
- Choose Extensions (or Add-ons in older versions), find uBlock Origin by Raymond Hill, and tap the plus button. You can also open the official Android listing in Firefox.
- Read the requested permissions and tap Add. If you want it to work in private tabs, enable the optional private-browsing setting.
- Open a normal website in Firefox. From the Extensions menu, open uBlock Origin and check that its power button is on.
These steps follow Mozilla’s Android installation guide. Blocking applies to websites in Firefox, including YouTube’s website when supported by the current filters. It does not filter Chrome, the YouTube app, or other Android apps.
Firefox on iPhone and iPad cannot run this extension. For those devices, see Lite for Safari on iPhone and iPad.
Recommended Settings for Most Users
Filter lists worth enabling
Start with the defaults, including EasyList, EasyPrivacy, and uBlock Origin’s own filters. If you want to hide more interruptions, review the optional Annoyances and cookie-notice lists in the dashboard. Enable only what you need, and undo the change if a site breaks.
If you browse in languages other than English, enable only the regional list that matches your browsing. Turning on every regional list at once is unnecessary and can slow down troubleshooting later.
One setting most people miss
The dashboard’s I am an advanced user setting enables dynamic filtering. Leave it off unless you understand those controls; the default setup is suitable for most users. The request logger is available without enabling advanced mode. See the advanced features documentation before changing this setting.
Firefox + uBlock Origin vs. Chrome
Firefox supports the full uBlock Origin engine. Current Chrome supports Lite, which uses Manifest V3 and has different filtering capabilities. See the Chrome migration guide for your options, or the Lite guide for modes, custom filters, and limitations.
Firefox
- Full uBlock Origin support
- Dynamic filtering available
- Better fit for heavier filter setups
- Best option if Chrome disabled your blocker
Chrome
- uBlock Origin Lite only
- Manifest V3 rule and capability limits
- Reduced flexibility for advanced users
- A practical option for staying in Chrome
Troubleshooting Common Firefox Issues
uBlock Origin is installed but not blocking
- Open
about:addonsand confirm the extension is enabled. - Open the dashboard, go to Filter lists, and click Update now.
- Check the site is not whitelisted. If the power button is blue for that site, blocking is on.
Firefox feels slower after enabling extra lists
This is uncommon, but it can happen when too many optional lists are enabled at once. Turn off lists you do not need first, especially extra regional or niche annoyance lists, then retest.
YouTube ads are still showing
Update Firefox, uBlock Origin, and your default filter lists. Confirm blocking is enabled for YouTube, temporarily disable conflicting blockers or custom YouTube filters, and test in a new tab. If ads persist, follow the official uBO YouTube troubleshooting thread. Blocking can change as YouTube updates its systems.
What uBlock Origin Can’t Do on Firefox
uBlock Origin is excellent inside the browser. It does not block ads inside native mobile apps, smart TV apps, or traffic that never passes through Firefox. iOS is its own limitation as well, because Firefox on iPhone and iPad cannot run the desktop extension model.
Where DNS blocking fits
A DNS blocker can block requests to known advertising and tracking domains from apps and devices configured to use it. It can complement Firefox filtering, but cannot hide page elements or selectively remove ads delivered from the same domains as wanted content, such as YouTube video ads. Apps that use another DNS resolver may bypass it. See how DNS filtering differs from browser filtering.
Options include uBlockDNS, NextDNS, and AdGuard DNS. Check each service’s current features and limits before choosing.
Disclosure: uBlockDNS is a separate service operated by this website’s maintainer. It is not affiliated with or endorsed by the uBlock Origin project or Raymond Hill. No DNS service is required to use uBlock Origin.