Firefox has a good reputation for privacy, and most of it is earned. The catch is that a fair amount of what makes it good is switched off, or set to its mildest level, on a fresh install. Mozilla picks defaults that keep every website working for every user, which is a sensible choice for them and not always the best one for you.
The good news is that none of this takes long. Everything below lives in the regular Settings page, there is no need to go digging through about:config, and you can undo any of it in a few seconds if a site misbehaves.
One practical note before you start. Mozilla reorganized the Settings pages in 2026, so a menu path from an older tutorial may no longer match what you see. The search box at the top of the Settings page is the quickest way around that. Type the name of the option and Firefox takes you straight to it, whichever version you are running.
1. Move Enhanced Tracking Protection to Strict
Enhanced Tracking Protection is the feature doing most of the work, and it ships in Standard mode. Standard already blocks social media trackers, cross-site tracking cookies, fingerprinters and cryptominers. What it holds back is tracking content, such as the scripts hidden inside ads and embedded widgets, which it only blocks in private windows.
Strict applies that blocking to every window. Search Settings for "Enhanced Tracking Protection" and pick Strict.
People avoid this setting because they have heard it breaks websites. It can, now and then, but Firefox keeps a list of compatibility fixes for major problems that stays on by default even in Strict. If a login button or a checkout page still refuses to work, click the shield icon next to the address bar and turn protection off for that one site. That is a much better trade than running the weaker setting everywhere.
2. Turn on HTTPS-Only Mode
Most of the web is encrypted by now, but not all of it, and an old bookmark or a mistyped address can still land you on a plain HTTP page. HTTPS-Only Mode makes Firefox ask for the secure version of every site first.
Search Settings for "HTTPS-Only" and enable it in all windows. There is also an option to use it in private windows only, which is a half measure. When a site has no secure version at all, Firefox stops and shows a warning, and you decide whether to carry on. In practice you will see that page a handful of times a year, usually on a very old site or a router's admin panel.
3. Decide who answers your DNS lookups
Every time you visit a site, your browser first has to look up its address. Traditionally that request goes out unencrypted, which means your internet provider, or whoever runs the Wi-Fi you are on, can see the name of every site you open. DNS over HTTPS wraps those lookups in encryption.
Firefox offers a few levels. Default Protection lets the browser decide when to use secure DNS and falls back to your normal resolver if anything goes wrong. Increased Protection keeps it on all the time with a provider you choose. Max Protection never falls back quietly and shows a warning if the secure lookup fails.
Increased is the sweet spot for most people. Max is the stricter choice, though it can get in the way on hotel and airport networks that rely on a sign-in page.
4. Tell websites not to sell your data
If you went looking for the old Do Not Track checkbox recently and could not find it, you did not imagine it. Mozilla removed it in Firefox 135 because so few websites ever honored the request.
Its replacement is Global Privacy Control, which appears in Settings as "Tell websites not to sell or share my data". The difference is that this signal has legal backing in some places, California being the best-known example. It is one checkbox, it costs nothing, and it is off until you tick it.
5. Review what Firefox sends back to Mozilla
Firefox collects usage data too. It is far less than most browsers gather and Mozilla is open about what it includes, but it is still your call. Search Settings for "data collection" and you will find a short list of checkboxes, including one for sending technical and interaction data to Mozilla, one for the daily usage ping, and one that lets Firefox run feature studies on your installation.
The detail that catches people out is that these are separate switches. Turning off technical and interaction data does not turn off the daily usage ping, so untick both if you want both gone.
6. Check your proxy settings
This one gets skipped because it sits deep in the menus, yet it is one of Firefox's more useful quirks. Chrome and Edge simply borrow whatever proxy your operating system uses. Firefox has its own connection dialog, so you can send the browser's traffic through a proxy while every other app on the machine connects as usual.
There are two reasons to look. The first is a quick audit. Search Settings for "proxy", open the dialog, and make sure nothing is filled in that you did not put there yourself. An unfamiliar proxy address can be left behind by old software or by an extension, and everything you browse passes through it.
The second reason is doing it on purpose. A proxy hides your real IP address from the sites you visit and lets you appear from a different country or city, which tracking protection alone cannot do. The dialog has a few traps, though. There are no fields for a username and password, so Firefox asks for them when you load the first page. You have to tick "Also use this proxy for HTTPS", otherwise secure sites, which is nearly all of them, skip the proxy entirely. And SOCKS5 proxies that need a login do not work without an extension. This guide to proxy settings in Firefox walks through each step, including where the menu ended up after the redesign.
Keep your expectations realistic here. A proxy changes your IP address, not your cookies. A site you are already signed in to still knows exactly who you are, so pair the proxy with a private window or a separate profile if you want a clean start.
7. Clear cookies when you close the browser
Firefox already keeps each site's cookies in a separate jar, a feature Mozilla calls Total Cookie Protection, and it is on by default. That stops one site from reading another site's cookies. It does not stop a site from recognizing you every time you come back.
If that bothers you, search Settings for "cookies" and turn on the option to delete cookies and site data when Firefox is closed. You will have to sign in again more often, so add exceptions for the few sites you use every day and let the rest reset.
Ten minutes, then leave it alone
None of these settings will make you invisible, and anyone promising that from a browser checkbox is selling something. What they do is cut down the amount of information you hand over by default, and they keep doing it quietly after you close the Settings tab.
If you only have time for two, make them Strict tracking protection and HTTPS-Only Mode. Come back for the rest when you have a spare coffee break. It is also worth opening the Settings page again after a big Firefox update, since new options tend to arrive switched off.