In interface design, a tab is a graphical user interface object that allows multiple documents or panels to be contained within a single window, using tabs as a navigational widget for switching between sets of documents. It is an interface style most commonly associated with web browsers, web applications, text editors, and preference panes, with window managers, especially tiling window managers, being lesser known examples.

Tabs are modeled after traditional card tabs inserted in paper files or card indexes (in keeping with the desktop metaphor).

Tabs may appear in a horizontal bar or as a vertical list, of which the former takes typically less screen space whereas the latter can show more items at once while still having space for individual titles. Horizontal tabs may have multiple rows. Tabs may be organizable by changing their order through drag and drop or creating a separate window from an existing tab. Implementations may support range-selecting multiple tabs for moving, closing, and separating them.