Mozilla Firefox includes a built-in spelling checker that operates actively in the background. As you type into text boxes, comment sections, or web-based email clients, Firefox will automatically place a jagged red line under any word it doesn’t recognise. While excellent for catching typos, this feature can be incredibly frustrating if you frequently type in multiple languages, use heavily specialised technical jargon, or are typing code snippets into a browser-based editor. The constant red squiggles can make text difficult to read. If you prefer to manage your own spelling, you can easily turn this feature off.
How to Disable the Spelling Checker
You can turn off the “check as you type” feature globally from the main Firefox settings menu.
- Open the Mozilla Firefox browser.
- Click the Application Menu button (the three horizontal lines) in the top-right corner of the window.
- Select Settings from the drop-down list.
- Ensure you are on the General tab in the left-hand menu pane.
- Scroll down the page until you find the section titled Language and Appearance.
- Under the “Language” sub-heading, locate the checkbox labelled Check your spelling as you type.
- Click the checkbox to uncheck it.
The change takes effect immediately. The jagged red lines will vanish from any text boxes you currently have open, and Firefox will no longer flag unusual words as errors, providing a much cleaner typing experience across all websites.