A Tabbed Document Interface (TDI) is one that relies on tabbed panes to hold child windows instead of different windows as in a Multiple Document Interface.

Internet web browsers are notable for implementing this kind of interface (called tabbed browsing), an approach pioneered by Opera and subsequently adopted by Mozilla and a number of others. As of January 2004, almost all graphical web browsers except for Internet Explorer and OmniWeb support a TDI. OmniWeb has announced that OmniWeb 5, a beta of which is planned to be released around Februrary 2004, will support visual tabbed browsing.

One important advantage of the tabbed document interface is that it holds many different documents logically under the one window, instead of holding a lot of small child windows, though, if too many documents are open, the tabs can be rather difficult to manage or label.

The major disadvantage is that users are restricted to viewing one window at a time, something which can be done with MDI.

Document interface comparison: