WTL was created by Microsoft employee Nenad Stefanovic for internal use and later released as an unsupported add-on to Visual Studio and the Win32 Framework SDK.

WTL provides support for implementing various user interface elements, from frame and popup windows, to MDI, standard and common controls, common dialogs, property sheets and pages, GDI objects, and other common UI elements, such as scrollable windows, splitter windows, toolbars and command bars.

Other classes such as a string wrapper that is syntax-compatible with MFC's CString and some templated collections are also included.

Most of the WTL API is a mirror of the standard Win32 calls, so the interface tends to be familiar to most Windows programmers.

In 2004 Microsoft made the complete source code available under the Common Public License and released it through SourceForge.