You can look at the CTR extension.

• https://addons.mozilla.org/firefox/addon/classicthemerestorer/

Look at the setting(s) in the CTR Options/Preferences here:

• CTR Options Location Bar (1): "Hide zoom button (if present)"

For a solution with userChrome.css/stylish, also see:

• [/questions/1155400] How could I remove the zoom indicator from address bar?

Is there another way to remove it without installing additional add-ons? Its very annoying in small monitors, where you need to use zoom every time and optimize the screen space.

You can alternatively do this with code in userChrome.css without using an extension like I posted here:

• https://support.mozilla.org/questions/1155400#answer-956966

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

#urlbar-zoom-button {display:none!important}