The Finder is the default application program used on the Mac OS and Mac OS X operating systems that is responsible for the overall user-management of files, disks, network volumes and the launching of other applications. As such the Finder acts like the shell on other operating systems, but using a graphical user interface. It was introduced with the very first Macintosh computer, and also existed as part of GS/OS on the Apple II GS . It underwent a complete rewrite with Apple's switch to a UNIX-based OS in Mac OS X.

The Finder is the first program a user interacts with after booting a Mac (and potentially logging in), and as such it is responsible for the general look and feel of the machine. One should be careful to distinguish this from the actual GUI of the machine, which is really provided by particular services within the operating system (eg, WindowServer). The Finder is just another application, albeit the default one. It can even be closed if the user knows how, although it is difficult to replace completely. One could compare it to Windows Explorer in Microsoft Windows, the Tracker in BeOS, Nautilus in GNOME, and Dolphin or the file management aspect of Konqueror in KDE.

The Finder maintains a view of the file system that is rendered using the desktop metaphor - that is, the files and folders are represented as appropriate icons, volumes are displayed on the desktop, and there is a trash can (on the Dock in OS X, on the desktop in previous versions) to which files can be dragged to mark them for deletion.