The Object Windows Library (OWL) was a Borland library, which was an object-oriented wrapper around the Win16 API. It was used in Turbo Pascal for Windows, Borland Pascal and their C++ package.

It was deprecated in favour of Visual Component Library (VCL), which is a part of Borland's Delphi and C++Builder packages.

A community on the Internet has released a series of patches to the original OWL source code to allow compilation under other compilers (Such as Microsoft Visual C++) and add new features under the project name OWLNExt.