By default, Firefox will display a small x on each tab to close it. When there are a large number of tabs, Firefox will display a small x only on the active tab. In either case, you should be able to close the tab using either of these: * right-click > Close Tab<br>''Choose carefully, as you probably do not want to accidentally close all other tabs'' * Ctrl+w to close the active tab There are many tab-related add-ons that could enhance or replace this feature, so if it doesn't work as described, could you let us know whether you have such an add-on? Most likely it would appear here: orange Firefox button (or Tools menu) > Add-ons > Extensions category Does that help?