Windows Hardware Quality Labs testing or WHQL Testing is Microsoft's testing process which involves running a series of tests on third-party (i.e. non-Microsoft) hardware or software, and then submitting the log files from these tests to Microsoft for review. The procedure may also include Microsoft running their own tests on a wide range of equipment, like different hardware and different Microsoft Windows editions.

Products that pass the WHQL tests get to use a "Certified for Windows" logotype, which certifies that the hardware or software has had some share of testing by Microsoft to ensure compatibility. The actual logo used depends on the version of Windows.