It depends... When you use the Library window (Manage bookmarks) you can sort your bookmarks by any column, ascending or descending. However, that doesn't change the order of the bookmarks, it's just for convenience of searching/editing. If you want to alphabetize a folder of bookmarks, you can right-click the folder (with one button, Ctrl+click), and choose Sort by Name. You can do that in the left column of the Library window, or in the Bookmarks Sidebar, whichever is more convenient. Unfortunately, Firefox doesn't have any built-in options to sort by other criteria such as date added, and it doesn't constantly update the list with your preferred sort order. For those, you could consider using an add-on such as one of the following (please read their reviews before installing): * https://addons.mozilla.org/firefox/addon/sort-bookmarks-webext/ * https://addons.mozilla.org/firefox/addon/auto-sort-bookmarks/ Hopefully somewhere in there, we can solve this for you?