The fast route
Open the ☰ menu at the top right, choose Settings, click Search in the left sidebar, and pick from the Default Search Engine dropdown. Typing about:preferences#search into the address bar goes to the same screen in one step.
These paths describe Firefox on desktop as of August 2026. Firefox has kept this panel in the same place across many releases, and unlike Chrome and Edge it puts the default engine, the private-window engine, the suggestion toggles and the per-engine shortcuts on a single screen.
Firefox on Windows, macOS and Linux
- Click the ☰ button at the top right of the window — the application menu.
- Choose Settings.
- Select Search in the left sidebar.
- Open the Default Search Engine dropdown and choose an engine.
- If private windows should use the same engine, tick the option to use this search engine in private windows; leave it unticked to set a different one there.
The change applies immediately to the address bar and, if you have added one, the separate search bar in the toolbar. There is no restart and no confirmation.
The same panel carries two things worth a glance while you are there. Search Suggestions controls whether what you type is sent to the engine for autocomplete before you press Enter, with separate boxes for the address bar and for private windows — a different question from which engine handles the finished query. And the Search Bar setting decides whether the toolbar shows a dedicated search box alongside the address bar or the address bar handles both jobs.
Search shortcuts and one-off searches
At the bottom of the Search panel is a table of engines with keyword shortcuts beside them. These are not defaults; they are prefixes. Typing the shortcut, a space, and then a query sends that one search to that engine while leaving your default alone — useful if you want an independent index most of the time and a mainstream one for the occasional stubborn lookup, without touching the setting twice a day.
Firefox also offers one-off engine buttons beneath the address bar as you type, which do the same thing by clicking rather than typing. Engines cannot be added from this panel — Mozilla’s own documentation is explicit about that. What the panel offers instead is a Find more search engines link at the foot of the list, which opens the Firefox Add-ons site, where an engine ships as an add-on. An engine that publishes a standard search description can also be added from the site itself, and the entry then appears in the same table.
The distinction matters when diagnosing an unexpected result: a search that went somewhere strange may have gone through a shortcut or a one-off button rather than through a changed default.
The new tab page
Firefox does not keep a separate engine for its home and new-tab pages. The search box on Firefox Home hands queries to the same default engine as the address bar, so there is no second setting to hunt for — a real difference from Microsoft Edge, where the new-tab box is governed independently and stays on Bing until a second control is changed.
If you would rather the new-tab page had no search box at all, that is a display option in the Home panel of settings, under the controls for what Firefox Home shows. Removing the box does not change which engine the address bar uses.
Firefox on Android and iOS
On both mobile builds the route is the ☰ menu, then Settings, then Search, then the default engine entry at the top of that screen. The mobile Search screens also carry the suggestion toggles and, on Android, the list of alternative engines available for one-off searches.
As always on a phone, this changes Firefox alone. On iPhone and iPad, Firefox cannot alter what Safari does, and links opened from other apps go to whichever browser is set as the system default browser.
Why the setting reverts
Firefox does not change the engine by itself. Four things do.
- An add-on has taken it over. Extensions may declare a search provider, and Firefox shows a prompt when one asks to. Once granted, the dropdown reflects the add-on's choice. Open the ☰ menu, then Add-ons and themes, and remove the extension responsible — changing the dropdown while it is installed does not hold.
- An enterprise policy is in force. Firefox supports administrative policies that can set or lock the default engine, and a policy file left behind by bundled software behaves exactly like one deployed by an employer. Open
about:policiesto see what is active. On a personal machine, an active policy you did not create is not normal. - Sync restored an older value. A signed-in Firefox account synchronises preferences between devices, so a machine still holding the previous engine can push it back.
- The profile was refreshed. The Refresh Firefox operation, and a newly created profile, both take the shipped default for your region.
Refresh Firefox resets the engine, add-ons and settings while preserving bookmarks, history and passwords. It removes the symptom, not the installer that caused it.
Preference or hijack
A change you made is one you can account for: you opened the Search panel, you chose an engine by name, and it stayed. Signs of something else:
- The engine changed after installing free software, not after opening Settings.
- The dropdown is greyed out, or
about:policieslists policies on a machine nobody manages. - Searches pass through an unfamiliar domain before landing on a mainstream results page — the redirect chain is the revenue, since traffic passed to a real engine earns a partner fee.
- The homepage and new-tab page changed at the same moment. Selecting a search engine does not touch either.
The repair differs accordingly. A preference is fixed in the dropdown; a hijack is fixed by finding the add-on, policy file or modified shortcut that keeps reapplying it.
Why Firefox ships with the engine it ships with
Firefox's pre-set engine is a commercial arrangement, and an unusually consequential one: search revenue from that default is, by wide reporting, the overwhelming majority of Mozilla's income. It has moved before. Yahoo! Search became the United States default under a five-year deal beginning in 2014; Mozilla exited early and returned to Google in November 2017, and litigation followed and was settled. A default engine is not a neutral technical choice by the browser maker, it is the thing that pays for the browser.
Which is a reason to make the choice deliberately. The dropdown lists engines with very different underpinnings: Google runs its own crawler and index; DuckDuckGo and Ecosia layer their own work over a partner's results; Startpage re-serves Google's results with the identifying data removed and says so plainly; Mojeek crawls and ranks an index of its own. Changing the setting changes who receives your query. Whether it changes the pages you are shown depends entirely on which of those you pick.
Frequently asked questions
Where is the default search engine setting in Firefox?
In the application menu, then Settings, then the Search panel in the left sidebar, at the dropdown labelled Default Search Engine. Typing about:preferences#search into the address bar opens the same screen directly. The setting applies immediately to the address bar and to the optional toolbar search bar, with no restart.
How do I use a different search engine in private windows?
The Search panel has an option, directly beneath the default engine dropdown, for using that same engine in private windows. Leave it unticked and Firefox lets you choose a separate engine for private browsing. This is one setting rather than two panels, so both engines are visible on the same screen.
Why does Firefox keep changing my search engine back?
Because an add-on, an enterprise policy or Firefox Sync is reapplying it. Add-ons must ask before taking over search, but the prompt is easy to accept while installing something else. Check Add-ons and themes, and check about:policies for active policies. On a personal machine, policies you did not create usually arrived with bundled software.
What are search shortcuts in Firefox?
They are keyword prefixes listed at the bottom of the Search panel. Typing a shortcut, a space and then a query sends that one search to that engine without changing your default. They are useful for keeping an independent engine as the default while sending the occasional query elsewhere, and they explain some searches that appear to have gone to the wrong place.
Does Firefox have a separate search engine for the new tab page?
No. The search box on Firefox Home uses the same default engine as the address bar, so there is only one setting to change. This differs from Microsoft Edge, where the new-tab search box is controlled separately and continues using Bing until a second setting is switched to the address bar.
Does changing the engine stop Firefox sending my keystrokes?
Not by itself. Search suggestions are separate checkboxes on the same panel, covering the address bar and private windows, and they send what you are typing to the engine before you press Enter. If reducing what leaves the browser is the reason for switching, those boxes matter alongside the engine dropdown.
Why is Google the default in Firefox?
Because of a paid distribution agreement. Search revenue from the default engine is, by wide reporting, most of Mozilla's income, which makes the pre-set engine a commercial arrangement rather than a technical recommendation. It has changed before: Yahoo held the United States default from 2014 until Mozilla returned to Google in November 2017.