Microsoft Windows Debugger (WinDbg) is a powerful Windows-based debugging tool. It is capable of both user-mode and kernel-mode debugging.

WinDbg provides full source-level debugging for the Windows kernel, kernel-mode drivers, and system services, as well as user-mode applications and drivers.

WinDbg uses the Microsoft Visual Studio debug symbol formats for source-level debugging. It can access any symbol or variable from a module that has PDB symbol files, and can access any public function's name that is exposed by modules that were compiled with COFF symbol files (such as Windows .dbg files).

WinDbg can view source code, set breakpoints, view variables (including C++ objects), stack traces, and memory. Its Debugger Command window allows the user to issue a wide variety of commands.

For kernel-mode debugging, WinDbg requires two machines (the host computer and the target computer). Kernel debugging is only supported on NT-based Windows operating systems.

WinDbg also supports various remote debugging options for both user-mode and kernel-mode targets.

WinDbg is the graphical-interface counterpart to CDB / NTSD and to KD.