A tree view or an outline view is a graphical user interface element (widget) that presents a hierarchial view of information. Each item (often called a branch or a node) can have a number of subitems. An item can be expanded to reveal subitems, if any exist, and collapsed to hide subitems.

Tree views are often seen in file manager applications, where they allow the user to navigate the file system directories. They are also used to present hierarchial data, such as an XML document. Extended tree view is the central component of an outliner application.